Heartworm Prevention For Great Danes? Top Answer Update

Heartworm Basics

Heartworms in dogs Heartworms in cats Heartworms in ferrets

Heartworm disease is a serious and potentially fatal disease affecting domestic animals in the United States and many other parts of the world. It is caused by foot-long worms (heartworms) that live in the heart, lungs, and associated blood vessels of affected pets, causing severe lung disease, heart failure, and damage to other organs in the body. Heartworm disease affects dogs, cats and ferrets, but heartworms also live in other species of mammals, including wolves, coyotes, foxes, sea lions and – in rare cases – humans. Because wild species such as foxes and coyotes live near many urban areas, they are considered important vectors of the disease.

Dogs. The dog is a natural host for heartworms, which means that heartworms that live inside the dog will mature into adults, mate and produce offspring. Left untreated, their numbers can increase, and dogs have been known to harbor several hundred worms in their bodies. Heartworm disease causes permanent damage to the heart, lungs, and arteries and can affect a dog’s health and quality of life long after the parasites are gone. For this reason, heartworm prevention in dogs is by far the best option, and treatment should be given as early as possible in the disease process, if necessary. Learn more about heartworm medication for dogs.

cats. Heartworm disease in cats is very different from heartworm disease in dogs. The cat is an atypical host for heartworm, and most worms in cats do not survive to adulthood. Cats with adult heartworm usually only have one to three worms, and many cats affected by heartworm do not have adult worms. While this means that heartworm disease in cats often goes undiagnosed, it’s important to understand that even immature worms cause real damage in the form of a condition known as heartworm-associated respiratory disease (HARD). Additionally, the medications used to treat heartworm infection in dogs cannot be used in cats, so prevention is the only way to protect cats from the effects of heartworm disease.

ferret. Heartworm disease in ferrets is caused by the same parasite that causes heartworm infection in dogs and cats. The disease in ferrets is an odd hybrid of the disease we see in dogs and cats. Like dogs, ferrets are extremely susceptible to infection and can carry greater numbers of worms than cats, but like cats, a small number of worms, perhaps just one, can cause devastating disease due to the heart’s small size. Heartworm disease in ferrets is often more difficult to diagnose, and there is no approved treatment. Prevention is essential for both indoor and outdoor ferrets.

How is heartworm disease transmitted from one pet to another?

The mosquito plays an essential role in the life cycle of the heartworm. Adult female heartworms that live inside an infected dog, fox, coyote, or wolf produce microscopic baby worms called microfilariae, which circulate in the bloodstream. When a mosquito bites an infected animal and takes a blood meal from it, it ingests these baby worms, which develop and mature into “infectious stage” larvae over a period of 10 to 14 days. Then, when the infected mosquito bites another dog, cat, or susceptible wild animal, the infective larvae are deposited on the animal’s skin surface and enter the new host through the mosquito’s bite wound. Once in a new host, it takes about 6 months for the larvae to develop into sexually mature adult heartworms. Adult heartworms can live 5 to 7 years in dogs and up to 2 or 3 years in cats. Due to the longevity of these worms, each mosquito season can result in an increasing number of worms in an infected pet.

What Are the Signs of Heartworm Disease in Dogs?

In the early stages of the disease, many dogs show few or no symptoms. The longer the infection lasts, the more likely symptoms will develop. Active dogs, dogs heavily infected with heartworm, or dogs with other health problems often show pronounced clinical symptoms.

Signs of heartworm disease may include a mild persistent cough, lack of exercise, tiredness after moderate activity, decreased appetite, and weight loss. As heartworm disease progresses, pets may develop heart failure and the appearance of a swollen abdomen due to excess fluid in the abdomen. Dogs with large numbers of heartworms can develop a sudden blockage in blood flow in the heart, resulting in a life-threatening form of cardiovascular collapse. This is called Caval’s syndrome and is characterized by sudden onset of shortness of breath, pale gums, and dark bloody or coffee-colored urine. Few dogs survive without prompt surgical removal of the heartworm blockade.

What Are the Signs of Heartworm Disease in Cats?

Signs of heartworm disease in cats can be very subtle or very dramatic. Symptoms may include coughing, asthma-like attacks, periodic vomiting, loss of appetite, or weight loss. Occasionally, an affected cat may have difficulty walking, experience fainting or seizures, or experience fluid buildup in the abdomen. Unfortunately, in some cases, the first sign is a cat’s sudden collapse or sudden death.

What are the signs of heartworm disease in ferrets?

The signs of heartworm disease in ferrets are similar to those in dogs, but they develop more quickly because the ferret’s heart is quite small. While dogs may not show any symptoms until they have lots of worms infecting their hearts, lungs, and blood vessels, just one worm can cause serious shortness of breath in a ferret. Symptoms of this exposure include • Lethargy (ie, fatigue, tiredness) • Open mouth and/or rapid breathing • Pale blue or muddy gum color • Cough

What is my pet’s risk of heartworm infection?

Many factors need to be considered, even if heartworm doesn’t seem to be a problem in your area. Your community may have a greater incidence of heartworm disease than you realize — or you may be unknowingly traveling with your pet to an area where heartworm is more common. Heartworm disease also spreads to new regions of the country every year. Stray and neglected dogs and certain wildlife such as coyotes, wolves, and foxes can be carriers of heartworm. Mosquitoes blown by wind over long distances and relocation of infected pets to previously uninfected areas also contribute to the spread of heartworm disease (this happened after Hurricane Katrina, when 250,000 pets, many infected with heartworm, were “adopted” and transported to the were shipped all over the world country).

The fact is, heartworm disease has been diagnosed in all 50 states and risk factors are impossible to predict. Several variables, from climate variability to the presence of wildlife carriers, cause infection rates to vary dramatically from year to year — even within communities. And since infected mosquitoes can get indoors, both outdoor and indoor pets are at risk.

For this reason, the American Heartworm Society recommends that you “think 12”: (1) have your pet tested for heartworm every 12 months, and (2) give your pet heartworm prevention 12 months of the year.

What do I need to know about heartworm testing?

Heartworm disease is a serious, progressive disease. The earlier it is detected, the better the chances that the pet will recover. When a dog, cat, or ferret is infected with heartworm, there are few, if any, early signs of illness. Therefore, it is important to detect their presence with a heartworm test performed by a veterinarian. The test only requires a small blood sample from your pet and works by detecting heartworm proteins. Some vets perform heartworm tests directly at their hospitals, while others send the samples to a diagnostic lab. In both cases, results are obtained quickly. If your pet tests positive, further testing may be ordered.

When should my pet be tested?

Testing procedures and timing differ somewhat between dogs, cats and ferrets.

Dogs. All dogs should be tested for heartworm infection annually, and this can usually be done during a routine check-up visit. The following are guidelines for testing and timing:

Puppies under 7 months old can be started on heartworm prevention without a heartworm test (it takes at least 6 months for a dog to test positive after infection), but should be retested 6 months after your first visit, 6 months later, and annually thereafter, to make sure they are heartworm free.

Adult dogs older than 7 months that have not previously received prophylaxis must be tested prior to starting heartworm prophylaxis. They too must be tested 6 months and 12 months later and annually thereafter.

You must consult your veterinarian and restart your dog on monthly prevention immediately – then retest your dog 6 months later. The reason for retesting is that heartworms must be around 7 months old before the infection can be diagnosed.

Annual testing is necessary, even when dogs are on heartworm prevention year-round, to ensure the prevention program is working. Heartworm medication is highly effective, but dogs can still become infected. Missing even one dose of a monthly medication or giving it too late can leave your dog vulnerable. Even if you administer the medication as recommended, your dog may spit up or vomit a heartworm pill — or rub off a topical medication. Heartworm preventatives are highly effective, but not 100 percent effective. If you don’t take your dog test, you don’t know your dog needs treatment.

cats. Heartworm infection in cats is harder to detect than in dogs because cats are much less likely than dogs to have adult heartworms. The preferred method of screening cats involves the use of both an antigen and an antibody test (the “antibody” test detects exposure to heartworm larvae). Your vet may also use X-rays or ultrasound to check for heartworm infection. Cats should be tested before being used for prevention and retested when the veterinarian deems appropriate to document continued exposure and risk. Since there is no approved treatment for heartworm infection in cats, prevention is crucial.

ferret. Diagnosing heartworm disease in ferrets can be more problematic. Your veterinarian may recommend both antigen testing and diagnostic imaging, such as echocardiography, to detect the presence of worms in the heart.

What happens if my dog ​​tests positive for heartworm?

No one wants to hear about their dog having heartworm, but the good news is that most infected dogs can be successfully treated. The goal is to first stabilize your dog if he is showing signs of illness and then kill all adult and immature worms while minimizing the side effects of the treatment.

Here’s what you should expect if your dog tests positive:

Confirm the diagnosis. Once a dog tests positive on an antigen test, the diagnosis should be confirmed with an additional – and different – test. Because the treatment regimen for heartworm is both expensive and complex, your veterinarian wants to be absolutely sure that treatment is necessary.

Once a dog tests positive on an antigen test, the diagnosis should be confirmed with an additional – and different – test. Because the treatment regimen for heartworm is both expensive and complex, your veterinarian wants to be absolutely sure that treatment is necessary. restrict exercise. This requirement can be difficult to meet, especially if your dog is used to being active. However, your dog’s normal physical activities will need to be restricted once the diagnosis is confirmed, as exercise increases the rate at which heartworm causes damage to the heart and lungs. The more severe the symptoms, the less activity your dog should have.

This requirement can be difficult to meet, especially if your dog is used to being active. However, your dog’s normal physical activities will need to be restricted once the diagnosis is confirmed, as exercise increases the rate at which heartworm causes damage to the heart and lungs. The more severe the symptoms, the less activity your dog should have. Stabilize your dog’s illness. Before actual heartworm treatment can begin, your dog’s condition may need to be stabilized with appropriate therapy. In severe cases of heartworm disease, or if a dog has another serious condition, the process can take several months.

Before actual heartworm treatment can begin, your dog’s condition may need to be stabilized with appropriate therapy. In severe cases of heartworm disease, or if a dog has another serious condition, the process can take several months. perform treatment. Once your vet has determined that your dog is stable and ready for heartworm treatment, he or she will recommend a multi-step treatment protocol. The American Heartworm Society has guidelines for developing this plan of attack. Dogs with no signs or mild signs of heartworm disease, such as a cough or exercise intolerance, have a high treatment success rate. More serious conditions can also be treated successfully, but there is a greater chance of complications. Heartworm disease severity does not always correlate with symptom severity, and dogs with many worms may have few or no symptoms early in the course of the disease.

Once your vet has determined that your dog is stable and ready for heartworm treatment, he or she will recommend a multi-step treatment protocol. The American Heartworm Society has guidelines for developing this plan of attack. Dogs with no signs or mild signs of heartworm disease, such as a cough or exercise intolerance, have a high treatment success rate. More serious conditions can also be treated successfully, but there is a greater chance of complications. Heartworm disease severity does not always correlate with symptom severity, and dogs with many worms may have few or no symptoms early in the course of the disease. Test (and prevent) success. Approximately 9 months after completing treatment, your vet will perform a heartworm test to confirm that all heartworms have been eliminated. To avoid the possibility of your dog getting heartworm disease again, take year-round preventative measures for the rest of his life.

What if my cat tests positive for heartworm?

Like dogs, cats can also be infected with heartworm. However, there are differences in the nature of the disease and how it is diagnosed and treated. Because a cat is not an ideal host for heartworm, some infections will heal on their own, although these infections can damage the cat’s respiratory system. Heartworms in the circulatory system also affect the cat’s immune system, causing symptoms such as coughing, wheezing and difficulty breathing. Heartworms in cats can even travel to other parts of the body like the brain, eye, and spinal cord. If the adult worms die in the cat’s body, serious complications can result, such as blood clots in the lungs and pneumonia.

Here’s what to expect if your cat tests positive for heartworm:

Diagnosis. While infected dogs can have 30 or more worms in their hearts and lungs, cats typically have 6 or fewer — and possibly just one or two. But while the severity of heartworm disease in dogs is related to the number of worms, in cats just one or two worms can make a cat very sick. Diagnosis can be complicated and requires a physical exam, an X-ray, a complete blood count, and several types of blood tests. An ultrasound can also be performed.

While infected dogs can have 30 or more worms in their hearts and lungs, cats typically have 6 or fewer — and possibly just one or two. But while the severity of heartworm disease in dogs is related to the number of worms, in cats just one or two worms can make a cat very sick. Diagnosis can be complicated and requires a physical exam, an X-ray, a complete blood count, and several types of blood tests. An ultrasound can also be performed. Treatment. Unfortunately, there is no approved drug therapy for heartworm infection in cats, and the drug used to treat infections in dogs is not safe for cats. However, cats with heartworm disease can often be helped with good veterinary care. The goal is to stabilize your cat and establish a long-term management plan.

Unfortunately, there is no approved drug therapy for heartworm infection in cats, and the drug used to treat infections in dogs is not safe for cats. However, cats with heartworm disease can often be helped with good veterinary care. The goal is to stabilize your cat and establish a long-term management plan. Monitor your cat. Heartworm-positive cats can clear heartworm spontaneously, but the damage they cause can be permanent. If your cat shows no signs of shortness of breath, but worms have been found in the lungs, chest x-rays every 6 to 12 months may be recommended. If mild symptoms are noted, small doses of prednisolone may be given to reduce inflammation.

Heartworm-positive cats can clear heartworm spontaneously, but the damage they cause can be permanent. If your cat shows no signs of shortness of breath, but worms have been found in the lungs, chest x-rays every 6 to 12 months may be recommended. If mild symptoms are noted, small doses of prednisolone may be given to reduce inflammation. Provide veterinary care. If the illness is severe, additional support may be needed. Your veterinarian may recommend hospitalization to conduct therapy, such as B. IV fluids, medicines to treat lung and heart symptoms, antibiotics and general nursing. In some cases, surgical removal of heartworms may be possible.

If the illness is severe, additional support may be needed. Your veterinarian may recommend hospitalization to conduct therapy, such as B. IV fluids, medicines to treat lung and heart symptoms, antibiotics and general nursing. In some cases, surgical removal of heartworms may be possible. Nurture prevention. A cat that has developed heartworm disease has shown to be susceptible to heartworm infection, and both outdoor and indoor cats are at risk. It’s important to give your cat monthly heartworm preventatives, which come in both drop and tablet form. Preventive measures prevent new infections from developing if an infected mosquito bites your cat again.

What if my ferret tests positive for heartworm?

Ferrets are extremely susceptible to heartworms. However, there are differences in the nature of the disease and how it is diagnosed and treated. Ferrets are extremely susceptible to heartworms. Heartworms in the circulatory system also compromise the ferret’s immune system, causing symptoms ranging from coughing, wheezing, and difficulty breathing to sudden death. Ferrets may also show fluid in the lungs, decreased appetite and weight loss, hind leg paralysis, or enlarged abdomen. Bilirubinuria (dark urine) is common in ferrets with heartworm disease.

Here’s what to expect if your ferret tests positive for heartworm:

diagnosis . Up to 14 heartworms have been found in a single ferret, but ferrets can be seriously affected by the presence of even one worm. Diagnosis can be complicated and requires a physical exam, an X-ray or ultrasound, a complete blood count, and various types of blood tests.

. Up to 14 heartworms were found in the treatment. Unfortunately, there is no approved drug therapy for heartworm infection in ferrets, and the drug used to treat infection in dogs is not safe for ferrets. Still, ferrets with heartworm disease can often be helped with good veterinary care. The goal is to stabilize your pet and establish a long-term management plan.

. Unfortunately, there is no approved drug therapy for heartworm infection in ferrets, and the drug used to treat infection in dogs is not safe for ferrets. Still, ferrets with heartworm disease can often be helped with good veterinary care. The goal is to stabilize your pet and establish a long-term management plan. Monitor your ferret. Most ferrets infected with heartworm show clinical signs. If worms are found in the lungs, a chest x-ray every 6 to 12 months may be recommended. If mild symptoms are noted, small doses of prednisolone may be given to reduce inflammation.

. Most ferrets infected with heartworm show clinical signs. If worms are found in the lungs, a chest x-ray every 6 to 12 months may be recommended. If mild symptoms are noted, small doses of prednisolone may be given to reduce inflammation. Provide veterinary care. If the illness is severe, additional support may be needed. Your veterinarian may recommend hospitalization to provide therapy, such as e.g. intravenously

Fluids, medicines to treat lung and heart symptoms, antibiotics and general nursing care. In rare cases, surgical removal of heartworms may be possible.

. If the illness is severe, additional support may be needed. Your veterinarian may recommend hospitalization to conduct therapy, such as B. IV fluids, medicines to treat lung and heart symptoms, antibiotics and general nursing. In rare cases, surgical removal of heartworms may be possible. Nurture prevention. Ferrets are very susceptible to heartworm disease and the consequences of infection can be devastating. Both outdoor and indoor ferrets are at risk and your ferret should receive monthly preventative care for life. Preventive measures prevent new infections from developing if an infected mosquito bites your ferrets again.

More questions about heartworm disease

Spanish

Your pet’s health is important. Learn the facts about heartworm disease to keep your pet healthy and heartworm-free.

dogs

cats

ferret

Heartworm Disease – What Is It and What Causes It?

Photo courtesy of Matt W. Miller, DVM, MS, Diplomat ACVIM (cardiology) Photo courtesy of Matt W. Miller, DVM, MS, Diplomat ACVIM (cardiology)

Heartworm disease is a serious disease that causes severe lung disease, heart failure, other organ damage, and death in pets, primarily dogs, cats, and ferrets. It is caused by a parasitic worm called Dirofilaria immitis. The worms are spread by a mosquito bite. The dog is the definitive host, meaning the worms mature into adults, mate, and produce offspring while living inside a dog. The mosquito is the intermediate host, meaning the worms live inside a mosquito for a short transitional period to become infectious (which can cause heartworm disease). The worms are called “heartworms” because the adults live in the heart, lungs, and associated blood vessels of an infected animal.

In the United States, heartworm disease is most common along the Atlantic and Gulf Coasts from the Gulf of Mexico to New Jersey and along the Mississippi River and its major tributaries, but it has been reported in dogs in all 50 states.

The heartworm life cycle in dogs

In an infected dog, adult female heartworms release their offspring, called microfilariae, into the dog’s bloodstream. When a mosquito bites the infected dog, the mosquito infects the microfilariae. Over the next 10 to 14 days and given the right environmental conditions, the microfilariae become infectious larvae while living inside the mosquito. Microfilariae must pass through a mosquito to become infectious larvae. When the infected mosquito bites another dog, the mosquito transmits the infectious larva to the dog through the bite wound. In a newly infected dog, it takes about 6 to 7 months for the infective larvae to mature into adult heartworms. The adult heartworms mate and the females release their offspring into the dog’s bloodstream, completing the life cycle. View a graphic of the heartworm life cycle in dogs.

Heartworm disease is not contagious, meaning a dog cannot get the disease if it is around an infected dog. Heartworm disease is only transmitted through a mosquito bite.

In a dog, the lifespan of a heartworm is 5 to 7 years. Adult heartworms look like cooked spaghetti, with males reaching about 4 to 6 inches in length and females about 10 to 12 inches in length. The number of worms living in an infected dog is called the worm load. The average worm load in dogs is 15 worms, but this number can range from 1 to 250 worms.

How is a dog tested for heartworm?

A vet uses blood tests to check a dog for heartworm. An antigen test detects specific heartworm proteins, called antigens, that are released into the dog’s bloodstream by adult female heartworms. In most cases, antigen testing can accurately detect infection with one or more adult female heartworms. The earliest that heartworm proteins can be detected in a dog’s blood is about 5 months after the bite of an infected mosquito.

Another test detects microfilariae in a dog’s bloodstream. Microfilariae in the bloodstream indicates that the dog is infected with adult heartworms (because only adult heartworms can mate and produce microfilariae). Microfilariae cannot be detected in a dog’s blood until about 6 months after being bitten by an infected mosquito (because it takes about that long for heartworms to develop from infective larvae into adults that mate and produce microfilariae).

When should a dog be tested for heartworm?

The timing and frequency of heartworm tests depend on many factors. Some of these factors are:

The dog’s age at the start of heartworm prevention;

If the owner forgot to give heartworm prophylaxis and for how long;

If the dog is switched from one type of heartworm prevention to another;

If the dog has recently traveled to an area where heartworm disease is more common; and

The length of heartworm season in the region where the dog lives.

Dogs 7 months of age and older should be tested for heartworm before starting heartworm prevention. A dog may appear healthy on the outside, but on the inside heartworms can live and thrive. If a heartworm-positive dog is not tested before beginning preventive care, the dog will remain infected with adult heartworm until it becomes sick enough to show symptoms. Heartworm preventatives do not kill adult heartworms. Also, prophylactic administration of a heartworm to a dog infected with adult heartworms can be harmful or fatal. If there are microfilariae in the dog’s blood, the preventative can cause the microfilariae to die suddenly, causing a shock reaction and possible death.

It is recommended that all dogs be tested annually for heartworm prevention. Talk to your dog’s vet about the best time for your dog’s annual heartworm test.

What Are the Symptoms of Heartworm Disease in a Dog?

The severity of heartworm disease depends on how many worms live in the dog (the worm load), how long the dog has been infected, and how the dog’s body responds to the presence of the heartworms. The dog’s activity level also plays a role in the severity of the disease and when symptoms first appear. Symptoms of heartworm disease may not be obvious in dogs that have a low worm load, have been recently infected, or are not very active. Dogs that are heavily wormed, have been infected for a long time, or are very active often show clear symptoms of heartworm disease.

There are four classes or stages of heartworm disease. The higher the class, the worse the disease and the more obvious the symptoms.

Class 1: No symptoms or mild symptoms such as an occasional cough.

Class 2: Mild to moderate symptoms such as an occasional cough and fatigue after moderate activity.

Class 3: More severe symptoms such as sickly appearance, persistent cough and fatigue after light activity. Difficulty breathing and signs of heart failure are common. In class 2 and 3 heartworm disease, heart and lung changes are usually seen on chest X-rays.

Class 4: Also called Caval’s Syndrome. There is such a heavy load of worms that blood returning to the heart is physically blocked by a large mass of worms. Caval syndrome is life-threatening, and prompt surgical removal of heartworms is the only treatment option. Surgery is risky, and even with surgery, most dogs with Caval syndrome die.

Not all dogs with heartworm disease develop Caval’s syndrome. However, if left untreated, heartworm disease will progress and damage the dog’s heart, lungs, liver and kidneys, eventually leading to death.

Is there a treatment for heartworm disease in dogs?

Melarsomine dihydrochloride (available under the trade names Immiticide and Diroban) is an arsenic-containing drug that is FDA-approved to kill adult heartworms in dogs. It is given by deep injection into the muscles of the back to treat dogs with stabilized heartworm disease classes 1, 2 and 3. Another drug, Advantage Multi for Dogs (Imidacloprid and Moxidectin), is FDA-approved to get rid of microfilariae in the dog’s bloodstream. Advantage Multi for Dogs is a topical solution that is applied to the dog’s skin.

Treating heartworm disease is not easy for the dog or the owner’s wallet. The treatment can be potentially toxic to the dog’s body and cause serious complications such as: B. Life-threatening blood clots in the dog’s lungs. Treatment is expensive, requiring multiple visits to the vet, blood tests, X-rays, hospital stays, and a series of injections.

The best treatment is prevention!

Many products are FDA approved to prevent heartworm in dogs. All require a veterinary prescription. Most products are administered monthly, either as a topical liquid applied to the skin or as an oral tablet. Both chewable and non-chewable oral tablets are available. A product is injected under the skin every 6 or 12 months and only a veterinarian can administer the injection. Some heartworm remedies contain other ingredients that are effective against certain intestinal worms (like roundworms and hookworms) and other parasites (like fleas, ticks, and ear mites).

It is best to prevent all year round! Speak to your dog’s veterinarian to decide which preventive agent is best for your dog.

The American Heartworm Society endorses “Think 12.” Give dogs 12 months of heartworm prevention and have them tested for heartworm every 12 months.

Can Cats Get Heartworm Disease?

Cats can also get heartworm after being bitten by an infected mosquito, although they’re not as susceptible to infection as dogs. A cat is not a natural host for heartworms because the worms don’t thrive as well in a cat’s body. Both indoor and outdoor cats are at risk of heartworm.

Is heartworm disease different in cats?

Heartworm disease in cats is slightly different than in dogs. Heartworms in cats don’t live as long (average lifespan is only 2 to 4 years) or grow as long, and fewer of them mature into adults. The worm load in cats is lower than in dogs. Usually a cat only has one or two worms. However, due to its relatively small body size, a cat with only a few worms is still considered heavily infected.

In cats, it takes 7 to 8 months for infective larvae to mature into adult heartworms and produce microfilariae. This is about a month longer than in dogs. The presence of microfilariae in a cat’s bloodstream is uncommon. Only 20 percent of cats with heartworm disease have microfilariae in their bloodstream, compared to 80 to 90 percent of dogs with heartworm disease. Also, the presence of microfilariae in the bloodstream is patchy and short-lived in cats.

It’s harder to spot heartworm infection in cats than in dogs. Veterinarians generally use two types of blood tests in combination to screen a cat for heartworm. However, negative test results do not rule out heartworm infection, and positive test results may or may not mean active heartworm infection is present. A vet will use the results of both blood tests, along with the cat’s symptoms and the results of other tests, such as X-rays and ultrasound of the heart, to determine if a cat has heartworm disease.

What Are the Symptoms of Heartworm Disease in Cats?

Not all cats with heartworm disease show symptoms. Some cats are able to rid themselves of heartworm spontaneously without showing any symptoms. However, some infected cats suddenly die of heartworm disease without ever showing any signs of illness. Cats with heartworm disease can have very non-specific symptoms that mimic many other feline diseases. These non-specific symptoms include vomiting, decreased activity and appetite, and weight loss. Cats with heartworm disease rarely show signs of heart failure.

In cats showing symptoms of heartworm disease, respiratory symptoms are most obvious due to the lung damage caused by the heartworms. Cats typically show symptoms of heartworm disease at two times – when the immature heartworms arrive in the arteries of the heart and lungs, and when the adult heartworms die.

The immature heartworms reach the heart and pulmonary arteries about 3 to 4 months after a cat is bitten by an infected mosquito. Many of these immature heartworms die, causing a severe inflammatory response in the cat’s lungs. This reaction is called heartworm-associated respiratory disease (HARD) because respiratory symptoms such as difficulty breathing, increased breathing rate, and coughing are the most obvious. It can be difficult to distinguish HARD from feline asthma or bronchitis.

When the adult heartworms die, they release toxins into the cat’s bloodstream that cause lung damage that leads to breathing problems or sudden death. Even the death of a worm can be fatal to a cat.

There is no FDA-approved drug to treat heartworm disease in cats, although symptoms can be managed with medication. Surgical removal of adult heartworms may be a treatment option if heartworms are visible on ultrasound. However, surgery is risky, and if the heartworms are not removed intact, there can be potentially serious complications, including shock and death.

Again, prevention is the best treatment!

Several products are FDA approved to prevent heartworm in cats. There are both topical and oral products for cats, and all are administered monthly and require a veterinarian’s prescription. Some heartworm remedies contain other ingredients that are effective against certain intestinal worms (like roundworms and hookworms) and other parasites (like fleas, ticks, and ear mites).

Again, year-round prevention is best! Talk to your cat’s veterinarian to decide what prevention is best for your cat.

Should cats be tested for heartworm?

It is recommended that cats be screened for heartworm before beginning heartworm prevention, although this pre-screening is less useful than in dogs. Talk to your cat’s vet about testing your cat for heartworm.

Photo courtesy of David A. Crum, DVM, MPH

What about heartworm disease in ferrets?

Ferrets can also get heartworm from the bite of an infected mosquito. Ferrets are similar to dogs in their susceptibility to heartworm infection, but their symptoms are more akin to cats.

Infected ferrets typically have a low worm load, and microfilariae are seen in the bloodstream in only 50 to 60 percent of ferrets with heartworm disease. Symptoms of heartworm disease in ferrets include decreased activity levels, coughing, difficulty breathing, and general weakness. In severe cases, heart failure can occur. Based on a ferret’s symptoms, a veterinarian may perform chest X-rays and an ultrasound of the heart to determine if it has heartworm disease. Blood tests for detecting heartworm infection in ferrets are generally unreliable.

No drug is approved by the FDA to treat heartworm disease in ferrets. And only one drug, Advantage Multi for Cats (imidacloprid and moxidectin), is approved to prevent heartworm in ferrets. It can only be obtained with a prescription and is a topical solution to be applied monthly. In addition to preventing heartworm, Advantage Multi for Cats also treats flea infestations in ferrets by killing adult fleas.

Again, prevention is the best treatment! Year-round prevention is recommended for all ferrets. Talk to your ferret’s vet about preventing heartworm disease in your furry friend.

Can Humans Get Heartworms From Their Pets?

Humans cannot get heartworms from their pets. Heartworms are only transmitted through the bite of an infected mosquito. In rare cases, people can get heartworms after being bitten by an infected mosquito. However, since humans are not a natural host for heartworms, the larvae usually migrate to the heart and pulmonary arteries and die before becoming adult worms.

How can I get more information about heartworm disease?

*Special thanks to David A. Crum, DVM, MPH for sharing his expertise on ferrets.

By Maria Strauss

People have learned about the benefits of a natural diet and limited vaccinations, and have seen the health improvements in their dogs from these changes. Now many want to know if they can stop giving their dogs heartworm preventatives or if they can be replaced with natural options.

Heartworm preventatives can cause serious side effects in some dogs, including depression, lethargy, vomiting, anorexia, diarrhea, dilated pupils, loss of balance, staggering, convulsions, and hypersalivation. Some dogs are particularly prone to side effects from ivermectin, the main ingredient in one of the most commonly used heartworm preventatives. Some of the preventatives are also combined with medications aimed at killing other pests such as fleas, mites, roundworms and hookworms.

On the other hand, heartworm can be a devastating disease. Dogs with moderate or severe infestations exhibit a chronic cough and are unable to exercise much as worms suffocate their heart and large blood vessels, reducing their blood (and therefore oxygen) supply. The disease often incapacitates its victims, unable to do much more than a slow walk without gasping for air, and kills many dogs. Even treating heartworm disease can be fatal, regardless of which method is used. Therefore, it’s important to understand the risks you run by not giving your dog a heartworm preventative.

In fact, most (certainly not all) holistic veterinarians consider the use of pharmaceutical preventatives to be less harmful than heartworm infection.

Some argue, but…

As a co-host of a dog health and nutrition email list, I often see people claim that as long as you have a healthy dog, feed him raw, and don’t over-vaccinate, your dog won’t get heartworm. If only that were true! These measures can help to a certain extent, but they are not foolproof. The only way to be sure your dog is protected is to give heartworm prevention.

Christie Keith, who lives in an area of ​​Northern California where heartworm is relatively uncommon and who has been raising Scottish Deerhounds naturally for over 19 years, learned this the worst way.

“I have not used any allopathic prevention on my dogs for 16 years. At the end of those 16 years, routine testing revealed that two of my dogs were heartworm positive,” says Keith. “One of the positive dogs was Raven, a Deerhound I bought from another breeder. She came to me at 17 weeks with a bad ear infection and severe allergies and no one could claim that Raven was healthy or had a normal immune system.

“By contrast, my dog, Bran, was a third-generation, naturally raised, home-bred dog. He was not vaccinated against rabies except minimally. He was fed raw. His mother and her mother were fed raw and not vaccinated except minimally against rabies. He was, by any available definition, extremely healthy and robust. He had never been sick a day in his life.”

Christie successfully treated her two dogs, although Raven nearly died from a pulmonary embolism during treatment. Bran became heartworm-free after months of using the “slow-kill” method of heartworm treatment with no evidence of side effects. Unfortunately, Bran died shortly thereafter from acute kidney failure. Autopsy results were inconclusive, showing that Bran had glomerulonephritis, but not why.

While searching for the cause of her dog’s death, Christie discovered that glomerulonephritis is a possible side effect of heartworm infection. Although she and her vets eventually concluded that Bran’s kidney failure was caused by Lyme nephritis rather than heartworm disease, it was disconcerting to realize that heartworm can affect more than just the heart and lungs.

“I have no intention of ever experiencing what I went through with Raven and Bran. I can’t stay silent when I see people beginning to believe that healthy animals don’t get heartworm and that unless we overvaccinate and feed raw, we can safely go without preventatives. It just isn’t like that. And it’s not realistic to rely on our dogs’ health and natural disease resistance to protect them from a threat they often face, as is the case in heartworm-endemic areas.

“No living being is in a static state of health 24 hours a day, 7 days a week. If our dogs are exposed to an infectious parasite frequently, they can eventually succumb to it, no matter how healthy they typically are.”

“Alternative” prevention?

Some holistic practitioners recommend various herbal or homeopathic supplements for heartworm prevention, and anecdotal evidence from some dog owners can be found on many discussion lists devoted to natural dog care. However, consumers should be aware that none of these alternatives have been evaluated for safety or effectiveness, nor are there studies to suggest they are effective in protecting against heartworm infection. Additionally, some herbal dewormers such as wormwood and black walnut are potentially toxic when used in dosages needed to control intestinal parasites.

Some homeopathic practitioners advocate the use of homeopathic nosodes for heartworm prevention. Again, there are no studies showing they are effective. In his book Homeopathic Care for Cats and Dogs, Don Hamilton, DVM says: “I know of a few cases where the nosode was not protective. I believe it offers some protection, although it may be incomplete. … If you decide to try the nosode, you must understand that its effectiveness is currently unknown.”

What is known is that conventional heartworm prevention is the best form of protection currently available. Luckily for those of us who are concerned about the side effects of using conventional medicines for prevention, there are numerous ways you can minimize their use and still protect your dog. I will discuss these methods after presenting the most common preventatives.

Conventional preventatives

The two most common (and generally considered safe) heartworm prevention ingredients in use today are ivermectin (used in Merial’s Heartgard and other products) and milbemycin oxime (used in Novartis’ Interceptor).

There is also an older daily heartworm preventative called diethylcarbamazine, or DEC. For many years, this drug was available from Pfizer as Filaribits. Although Filaribits has been discontinued, you can still find generic versions of DEC.

DEC is very safe in terms of side effects, but can be life-threatening when given to a heartworm-infected dog with circulating microfilariae due to the risk of rapid microfilariae death and a resulting anaphylactic reaction. Even going off medication for just a day or two can result in your dog becoming infected. If you are using DEC, it is important that you test for heartworm before starting this medication and every six months while using it. (Avoid Filaribits Plus, which has oxybendazole added to fight intestinal parasites and is known to cause liver damage.)

There are other heartworm products that contain drugs for other purposes. Heart-gard Plus adds pyrantel to control intestinal parasites including roundworms and hookworms. Adult dogs rarely have problems with roundworms, but if your yard is infested with hookworm, this product may be good until the hookworm is eliminated.

Sentinel is a combination of the products Interceptor and Program (Lufenuron). Lufenuron is a drug that prevents fleas from reproducing; It is not a pesticide and will not kill or deter fleas from biting your dog. This can be helpful for a short time when you have a flea infestation, and use several non-toxic methods to manage the flea problem, such as: B. diatomaceous earth to treat the house and nematodes to treat the garden.

I’m less enthusiastic about selamectin (found in Revolution by Pfizer), a more recent entry. Selamectin is a topical product that is also indicated for fleas, a species of tick, ear mites, and the mites that cause sarcoptic mange. While this can be great if your dog has had mange, fleas, ticks and ear mites, I prefer medications with a minimal and targeted effect over those with broad spectrum activity.

The injectable product moxidectin (ProHeart 6 by Fort Dodge) was pulled from the US market due to numerous reports of side effects, including death. I do not recommend the use of injectable heartworm preventatives at all as there is no way to remove them from your dog’s system if a bad reaction occurs and the sustained release medication will continue to affect your dog for months.

temperature and timing

So how can you reduce your dog’s exposure to conventional heartworm-prevention medication without reducing his protection from the nasty parasite?

First, in most parts of the country, it is not necessary to give heartworm prevention year-round. The development of the heartworm in the mosquito depends on the ambient temperatures. Heartworm larvae cannot develop to the stage necessary to infect dogs until day and night temperatures are above 14 degrees Celsius for at least a week or two. The duration depends on how warm it is; The warmer the temperatures, the faster the heartworm larvae develop.

If temperatures drop below this point at any point during the cycle, development can be prevented, but I wouldn’t count on that. Temperatures can vary depending on the mosquito’s habitat and may be warmer than the general ambient temperature under eaves or other sheltered areas.

Heartworm preventatives work by killing heartworm larvae that have already infected the dog but before they can mature into adult worms that cause damage. When you give your dog heartworm preventively, you kill any larvae that have infected your dog in the past month or two. Any larvae that have been in your dog for more than 60 days are more likely to survive the treatment and mature into adult worms.

Also, your dog may become infected the day after heartworm prevention; the drugs offer no future protection at all.

If your goal is to provide full protection for your dog with minimal medication administration, you need to monitor the temperatures in your area. Mosquitoes can transmit heartworm larvae to your dog about two weeks after your local temperature has stayed above 57 degrees Fahrenheit day and night.

Give the first preventive dose of the season four to six weeks after to destroy any larvae that have infected your dog during that time. Therefore, the first dose should be given six to eight weeks after daytime and nighttime temperatures have first exceeded 57°F. Continue to give the preventative every four to six weeks, with the last dose being given regularly after temperatures fall below this level.

For some parts of the country, this may mean that preventive drugs are only given between July and October, while in others, where temperatures remain mild year-round, they may need to be given year-round.

If you are not giving your dog heartworm prophylaxis (because the area you live in is very low risk or because the temperatures are not suitable for heartworm development) and then moving your dog to an area where heartworm is a problem , you must treat him with heartworm preemptively upon your return to protect him.

dosage amounts

With at least one medication, preventatively, you can give your dog less than the recommended dosage without compromising safety.

Milbemycin oxime, the active ingredient in Interceptor, has been approved by the FDA at one-fifth the regular dose to kill only heartworm without targeting intestinal parasites, including roundworms, whipworms, and hookworms. Novartis has a product, SafeHeart, with this lower dosage of milbemycin, but has not yet launched it.

The actual recommended dosage of milbemycin oxime for heartworm prevention only is 0.05 mg per pound of body weight (0.1 mg per kg). Compare this to Interceptor’s recommended dosage for controlling heartworm and intestinal parasites: 0.23 mg of milbemycin oxime per pound (0.5 mg/kg) of body weight. Heartworm can be prevented with a much lower dose than is required to control intestinal parasites.

SafeHeart contains 2.3 mg of mite mycin oxime for dogs 2 to 50 pounds and 5.75 mg for dogs 50 to 125 pounds. Interceptor contains 2.3 mg for dogs up to 10 pounds and 5.75 mg for dogs 11 to 25 pounds. So if your dog weighs more than 50 pounds, you can give the dog interceptor 11 to 25 pounds; otherwise you can use the for dogs up to 10 pounds.

frequency of preventive measures

It may not be necessary to give heartworm prevention every month. The monthly dosing schedule was designed to make it easy for people to remember when to administer the medication and to ensure dogs are still protected if a dose somehow fails to be swallowed or later vomited before absorption.

The FDA approvals cite studies showing that Heartgard, Interceptor and Revolution provide protection beyond 30 days. If you’re very careful about giving medication and you can watch your dog after giving the pill to make sure he isn’t spat out or later vomited, it can be safe to give heartworm preventatives less frequently than every 30 days use. Dosing your dog every 45 days is a conservative way to safely extend your dog’s dosing schedule.

Drug manufacturers’ pre-testing suggests that even longer dosing schedules can provide protection against heartworm – but I wouldn’t bet my dogs’ welfare on dosing schedules beyond a somewhat arbitrary 45 days.

The original FDA approval for Heartgard states: “The target dose of 6 mcg per kilogram body weight was selected from titration study 10855 as the lowest dose that provides 100 percent protection when the dosing interval was extended to 60 days to account for a missed dose simulate dose. ”

The original FDA approval for Interceptor states, “Complete (100 percent) protection was achieved in dogs treated 30 days post-infection, with 95 percent protection at 60 and 90 days.” This does not apply to SafeHeart, which was only tested in a dosing interval of 30 days.

The original FDA clearance for Revolution states: “Selamectin, applied topically as a single dose of 3 or 6 mg/kg, was 100 percent effective in preventing heartworm maturation in dogs after inoculation with infective D. immitis larvae 30 or 45 days prior to treatment, and 6 mg/kg [the recommended dosage level] was 100 percent effective in preventing heartworm maturation following inoculation of infective larvae 60 days prior to treatment.”

sharing pills

The problem of sharing heartworm pills is common. I spoke to representatives from Merial (maker of Heartgard) and Novartis (maker of Interceptor). Both said their active ingredients are mixed into their products before the pills are formed, so should be evenly distributed (although they can’t guarantee this). However, both manufacturers advise against pill splitting.

Splitting pills is inaccurate and can result in the dog getting less or more of the medication. If you decide to split the pills, use a pill splitter (available at any drug store) and try not to give the minimum dose as you cannot be sure your dog is getting enough of the medication.

No guarantees

It’s important to know that if you decide to change the way these drugs are administered – by splitting the pills, giving pills less than monthly, or using reduced dosages, then manufacturers’ guarantees will be voided. With normal use, if your dog develops a heartworm infection while taking one of these heartworm preventatives, the company will pay for the treatment. However, this does not apply if you use the medication in a manner different from what is stated on the label.

It’s important to understand the risk that heartworm infection poses to your dog. Rather than relying on unproven alternative methods of heartworm prevention, or relying on the unreliable method of relying on your dog’s health to protect him from infection, all of the methods outlined above give you options to avoid using traditional preventatives against heartworm safely while you are still giving your dog complete protection against heartworm infection.

Next month we’ll discuss treatment – what to do if your dog tests positive for heartworm.

-Mary Straus does part-time research on dog health and nutrition. She is the owner of the DogAware.com website. She lives in the San Francisco Bay Area with her dog Piglet.

Spanish

The bad news: Heartworm disease can be fatal to dogs, cats, and ferrets. The good news: you can protect your pet from this disease.

“It’s a preventable disease, which is why it’s so frustrating as a doctor when you see a case,” says Melanie McLean, D.V.M., a veterinarian with the U.S. Food and Drug Administration (FDA). Treatment can be difficult for animals, and McLean says it’s much easier and healthier for the pet to prevent the disease in the first place.

Heartworms are transmitted by infected mosquitoes, which transmit parasitic worms that grow in the arteries of the lungs and heart of dogs, cats, and other mammalian species, including ferrets. Heartworm larvae enter the bite wound and move through the pet’s body. They can grow up to 12 centimeters long.

The disease is not contagious from one pet to another, and human heartworm is very rare.

Use heartworm prevention medication year-round

The FDA has approved several heartworm prevention drugs for dogs and cats, but only one for ferrets so far. Treatment can vary by species, oral, injectable, or topical, but they all target heartworm larvae, not adults.

That’s one of the reasons veterinarians often recommend that pets receive heartworm prevention medication year-round. Although there are fewer mosquitoes in winter, there is still a risk that an animal will contract heartworm if the owner stops administering medication during this time of year.

“You never know when the first mosquito will come out or when the last mosquito will die. Heartworm has been reported in dogs in all 50 states, and just because you live in a state with a colder climate doesn’t mean your pet is safe,” warns McLean. Pet owners who do not give heartworm prevention medication during the winter run the risk of their pet contracting heartworm. If the pet becomes infected and you later pass on heartworm prevention without testing, you may be putting your pet at risk. The preventative drug can kill so many microfilariae (the offspring of adult female heartworms) at once that it could shock the animal’s system, with potentially fatal consequences. Also, as a preventive measure, the drug does not kill adult heartworms that continue to reproduce.

Testing for heartworm is important

Make sure your veterinarian tests your dog before you start using any heartworm prevention medication. (Preventive medications for dogs come in all three forms: oral, topical, and injectable. Talk to your vet about which one is best for your dog.) Dogs with heartworm may not show symptoms right away, and your vet may be able to guide your dog easily test with a simple blood test.

And even if you regularly treat your dog with preventive medication, your vet should test for heartworm annually. No drug is 100 percent effective, and you want to make sure the drug is working. In addition, the owners often forget to give the preventive medication for a month or more.

Cats and Ferrets: Pets also need heartworm prevention medication

Even if your pet rarely or never goes outside, they should still take heartworm prevention medication. Mosquitoes that transmit heartworms can easily enter the indoor environment (and thus your pet) through open doors and windows.

Heartworm does not survive as well in cats as it does in dogs, but cats are still at risk of heartworm disease. However, diagnosing heartworm in cats isn’t as easy, and the tests aren’t as easy or accurate as in dogs. In addition to the blood test, tests in cats may include x-rays and ultrasounds.

Unlike canine heartworm disease, there is no FDA-approved treatment to kill adult heartworm in cats. Because of the added complications associated with diagnosing and treating cats, prevention becomes the best weapon against feline heartworm. It’s best to treat indoor and outdoor cats year-round with an FDA-approved medication to prevent heartworm. For cats, there are both topical and oral medications available for prevention.

Testing for heartworm in ferrets is also not as easy, simple, or as reliable as it is in dogs. No drugs are FDA-approved to treat heartworm disease in ferrets, so prevention is crucial. There is one drug (Advantage Multi for Cats) that is approved to prevent heartworm in ferrets. It is a topical medication and is also useful for killing adult fleas.

Useful tips about heartworm and your pet

Horacio asked a good question in the comments section of my recent heartworm-related post.

Horacio posted a comment on Jul 26, 2010 at 10:24am

If I’ve been giving my dog ​​heartworm prevention every month but missed a few appointments for some reason. Is there a risk of restarting with the preventive medicines?

Horacio, you are certainly not the first person in the world to overlook your dog’s heartworm prevention. Your situation is an ordinary one.

Any time a dog goes more than six weeks without heartworm prevention, the dog is at risk of infection. Dogs with adult infections (where heartworms mate and produce larvae in the bloodstream) can experience a shock-like side effect to heartworm prevention. Mature infections take four to six months to develop.

In other words, four to six months past six weeks, heartworm medication could put a dog at risk.

However, I am happy to say that the side effect described above is very rare.

Horacio, I recommend having your vet do a heartworm test on your dog. Repeat the test after four to six months (the test can only detect mature heartworm infections). Restart your dog’s heartworm prevention program after getting a negative result on the first test. In almost all cases, the benefits of resuming medication outweigh the risks.

heartworm in dogs

Information on heartworm positive dogs

What is heartworm disease?

Heartworm disease is a serious and potentially fatal disease affecting domestic animals in the United States and many other parts of the world. It is caused by foot-long worms (heartworms) that live in the heart, lungs, and associated blood vessels of affected pets, causing severe lung disease, heart failure, and damage to other organs in the body. Heartworm disease affects dogs, cats and ferrets, but heartworms also live in other species of mammals, including wolves, coyotes, foxes, sea lions and – in rare cases – humans. Because wild species such as foxes and coyotes live near many urban areas, they are considered important vectors of the disease.

Dogs. The dog is a natural host for heartworms, which means that heartworms that live inside the dog will mature into adults, mate and produce offspring. Left untreated, their numbers can increase, and dogs have been known to harbor several hundred worms in their bodies. Heartworm disease causes permanent damage to the heart, lungs, and arteries and can affect a dog’s health and quality of life long after the parasites are gone. For this reason, prevention is by far the best option and treatment, if necessary, should be given as early in the disease course as possible.

cats. Heartworm disease in cats is very different from heartworm disease in dogs. The cat is an atypical host for heartworm, and most worms in cats do not survive to adulthood. Cats with adult heartworm usually only have one to three worms, and many cats affected by heartworm do not have adult worms. While this means that heartworm disease in cats often goes undiagnosed, it’s important to understand that even immature worms cause real damage in the form of a condition known as heartworm-associated respiratory disease (HARD). Additionally, the medications used to treat heartworm infection in dogs cannot be used in cats, so prevention is the only way to protect cats from the effects of heartworm disease.

How is heartworm disease transmitted from one pet to another?

The mosquito plays an essential role in the life cycle of the heartworm. Adult female heartworms that live inside an infected dog, fox, coyote, or wolf produce microscopic baby worms called microfilariae, which circulate in the bloodstream. When a mosquito bites an infected animal and takes a blood meal from it, it ingests these baby worms, which develop and mature into “infectious stage” larvae over a period of 10 to 14 days. Then, when the infected mosquito bites another dog, cat, or susceptible wild animal, the infective larvae are deposited on the animal’s skin surface and enter the new host through the mosquito’s bite wound. Once in a new host, the larvae take about 6 months to mature into adult heartworms. Adult heartworms can live 5 to 7 years in dogs and up to 2 or 3 years in cats. Due to the longevity of these worms, each mosquito season can result in an increasing number of worms in an infected pet.

What Are the Signs of Heartworm Disease in Dogs?

In the early stages of the disease, many dogs show few or no symptoms. The longer the infection lasts, the more likely symptoms will develop. Active dogs, dogs heavily infected with heartworm, or dogs with other health problems often show pronounced clinical symptoms.

Signs of heartworm disease may include a mild persistent cough, lack of exercise, tiredness after moderate activity, decreased appetite, and weight loss. As heartworm disease progresses, pets may develop heart failure and the appearance of a swollen abdomen due to excess fluid in the abdomen. Dogs with large numbers of heartworms can develop a sudden blockage in blood flow in the heart, resulting in a life-threatening form of cardiovascular collapse. This is called Caval’s syndrome and is characterized by sudden onset of shortness of breath, pale gums, and dark bloody or coffee-colored urine. Few dogs survive without prompt surgical removal of the heartworm blockade.

What is my pet’s risk of heartworm infection?

Many factors need to be considered, even if heartworm doesn’t seem to be a problem in your area. Your community may have a greater incidence of heartworm disease than you realize — or you may be unknowingly traveling with your pet to an area where heartworm is more common. Heartworm disease also spreads to new regions of the country every year. Stray and neglected dogs and certain wildlife such as coyotes, wolves, and foxes can be carriers of heartworm. Mosquitoes blown by wind over long distances and relocation of infected pets to previously uninfected areas also contribute to the spread of heartworm disease (this happened after Hurricane Katrina, when 250,000 pets, many infected with heartworm, were “adopted” and transported to the were shipped all over the world country).

The fact is, heartworm disease has been diagnosed in all 50 states and risk factors are impossible to predict. Several variables, from climate variability to the presence of wildlife carriers, cause infection rates to vary dramatically from year to year — even within communities. And since infected mosquitoes can get indoors, both outdoor and indoor pets are at risk.

For this reason, the American Heartworm Society recommends that you “think 12”: (1) have your pet tested for heartworm every 12 months, and (2) give your pet heartworm prevention 12 months of the year.

What do I need to know about heartworm testing?

Heartworm disease is a serious, progressive disease. The earlier it is detected, the better the chances that the pet will recover. When a dog or cat is infected with heartworm, there are few, if any, early signs of illness. Therefore, it is important to detect their presence with a heartworm test performed by a veterinarian. The test only requires a small blood sample from your pet and works by detecting heartworm proteins. Some vets perform heartworm tests directly at their hospitals, while others send the samples to a diagnostic lab. In both cases, results are obtained quickly. If your pet tests positive, further testing may be ordered.

When should my dog ​​be tested?

Test procedures and timing differ somewhat between dogs and cats.

Dogs. All dogs should be tested for heartworm infection annually, and this can usually be done during a routine check-up visit. The following are guidelines for testing and timing:

Puppies under 7 months old can be started on heartworm prevention without a heartworm test (it takes at least 6 months for a dog to test positive after infection), but should be retested 6 months after your first visit, 6 months later, and annually thereafter, to make sure they are heartworm free.

Adult dogs older than 7 months that have not previously received prophylaxis must be tested prior to starting heartworm prophylaxis. They too must be tested 6 months and 12 months later and annually thereafter.

If prevention has been missed (one or more late or missed doses), dogs should be tested immediately, then retested six months later and annually thereafter.

Annual testing is necessary, even when dogs are on heartworm prevention year-round, to ensure the prevention program is working. Heartworm medication is highly effective, but dogs can still become infected. Missing even one dose of a monthly medication or giving it too late can leave your dog vulnerable. Even if you administer the medication as recommended, your dog may spit up or vomit a heartworm pill — or rub off a topical medication. Heartworm preventatives are highly effective, but not 100 percent effective. If you don’t take your dog test, you don’t know your dog needs treatment.

What happens if my dog ​​tests positive for heartworm?

No one wants to hear about their dog having heartworm, but the good news is that most infected dogs can be successfully treated. The goal is to first stabilize your dog if he is showing signs of illness and then kill all adult and immature worms while minimizing the side effects of the treatment.

Here’s what you should expect if your dog tests positive:

Confirm the diagnosis. Once a dog tests positive on an antigen test, the diagnosis should be confirmed with an additional – and different – test. Because the treatment regimen for heartworm is both expensive and complex, your veterinarian wants to be absolutely sure that treatment is necessary.

Once a dog tests positive on an antigen test, the diagnosis should be confirmed with an additional – and different – test. Because the treatment regimen for heartworm is both expensive and complex, your veterinarian wants to be absolutely sure that treatment is necessary. restrict exercise. This requirement can be difficult to meet, especially if your dog is used to being active. However, your dog’s normal physical activities will need to be restricted once the diagnosis is confirmed, as exercise increases the rate at which heartworm causes damage to the heart and lungs. The more severe the symptoms, the less activity your dog should have.

This requirement can be difficult to meet, especially if your dog is used to being active. However, your dog’s normal physical activities will need to be restricted once the diagnosis is confirmed, as exercise increases the rate at which heartworm causes damage to the heart and lungs. The more severe the symptoms, the less activity your dog should have. Stabilize your dog’s illness. Before actual heartworm treatment can begin, your dog’s condition may need to be stabilized with appropriate therapy. In severe cases of heartworm disease, or if a dog has another serious condition, the process can take several months.

Before actual heartworm treatment can begin, your dog’s condition may need to be stabilized with appropriate therapy. In severe cases of heartworm disease, or if a dog has another serious condition, the process can take several months. perform treatment. Once your vet has determined that your dog is stable and ready for heartworm treatment, he or she will recommend a multi-step treatment protocol. The American Heartworm Society has guidelines for developing this plan of attack. Dogs with no signs or mild signs of heartworm disease, such as a cough or exercise intolerance, have a high treatment success rate. More serious conditions can also be treated successfully, but there is a greater chance of complications. Heartworm disease severity does not always correlate with symptom severity, and dogs with many worms may have few or no symptoms early in the course of the disease.

Once your vet has determined that your dog is stable and ready for heartworm treatment, he or she will recommend a multi-step treatment protocol. The American Heartworm Society has guidelines for developing this plan of attack. Dogs with no signs or mild signs of heartworm disease, such as a cough or exercise intolerance, have a high treatment success rate. More serious conditions can also be treated successfully, but there is a greater chance of complications. Heartworm disease severity does not always correlate with symptom severity, and dogs with many worms may have few or no symptoms early in the course of the disease. Test (and prevent) success. About 6 months after completing treatment, your vet will perform a heartworm test to confirm that all heartworms have been eliminated. To avoid the possibility of your dog getting heartworm disease again, take year-round preventative measures for the rest of his life.

More questions about heartworm disease

Despite the widespread availability of heartworm preventatives, an unfortunate number of dogs still develop heartworm infections. While many of us adopt heartworm-positive dogs, in which case heartworm treatment is simply part of the rescue process, many dogs of our own also have infections, often because owners are unaware of the risks or because owners are reluctant to spend money on monthly prevention Drugs whose benefits (when working properly) are not obvious. There are many stages of heartworm disease, from subclinical infections, where the dog will test positive but show no signs of the disease, to congestive heart failure, where the dog will actually die of its disease. There are many downsides to treating heartworm infection rather than preventing it.

Heartworm treatment is expensive; At the average neighborhood veterinary hospital, the total cost (from that rapid heartworm positive test to your heartworm-free dog) is often $1,000. Heartworms cause secondary changes in the dog’s heart and blood vessels, changes that cannot be reversed by treating the heartworm and therefore affect the dog’s lifelong health. Treating heartworm is not a benign process and comes with its own set of risks. Immiticide, the drug we give dogs to treat heartworm, is a very carefully regulated poison. It has been shown to be safe when administered correctly and at appropriate dosages; however, its use should not be taken lightly. This immiticide, given as a series of intramuscular injections, kills heartworms.

Unlike intestinal parasites, which can be easily excreted in the animal’s feces once killed, heartworms do not have an easy way to be excreted from the body after death. The dog’s immune system must break down the dead worms, an elimination process that is very effective but takes time. While this immune process is taking place, fragments of dead heartworms circulate in the bloodstream. These fragments can cause a variety of problems, the most common of which is physical obstruction of blood flow to the lungs. Because of these and other risks, the dog must be kept quiet and still without rigorous exercise or excessive play for six to eight weeks until we can be confident that all heartworms have been completely eliminated.

Because of the significant stress that heartworm treatment puts on a dog’s body, when you go to your regular veterinarian for heartworm treatment, they will first want to assess whether your dog is healthy enough to undergo treatment. The standard pre-treatment evaluation includes a full physical exam, confirmatory heartworm test, microfilial check (to see if heartworms are reproducing), full blood work, and X-rays. Depending on your particular situation, other tests may also be indicated. This diagnostic work-up allows your veterinarian to assess your dog’s general health, get an indication of the severity of the heartworm infection, and learn about changes that may have already occurred in the heart and lungs as a result of the heartworm infection. While this knowledge probably won’t stop the vet from treating your dog, it will allow them to tailor treatment and follow-up to each dog’s specific needs. Current heartworm treatment consists of three courses of Immiticide given over the course of a month. Due to the possibility of adverse events following these treatments, your dog will need to be hospitalized – maybe just for a day and maybe for several weeks. Heartworm treatment is something vets perform every day, but in the interest of the dog’s health, owner stress and owner wallet, it’s a procedure we want to avoid whenever possible.

Another heartworm treatment option, the slow-kill method, is also available. This method is often chosen when finances are an overwhelming issue or when a dog is not considered healthy enough to undergo immiticide treatment. This treatment involves administering ivermectin (in the form of monthly heartworm preventatives such as Heartgard and Iverhart) to a heartworm-positive dog. This treatment is not without risks and should not be undertaken without consulting a veterinarian. Giving Iverhart monthly will keep your dog’s heartworms from multiplying, which will help prevent your dog from being a source of infection for other dogs. It also prevents your dog from getting more adult heartworms. This treatment does not actually kill the worms, but shortens their lifespan; However, remember that the average heartworm can live for six years. So a shortening of that lifespan could still mean your dog has heartworm infection for four more years. While this slow-kill method prevents the infection from getting worse, it doesn’t prevent the secondary heart and lung changes that can eventually lead to heart failure.

Heartworm treatment is a carefully performed medical procedure. It is performed when the benefits are deemed to outweigh the risks, a decision made on a case-by-case basis for each individual dog. While it’s the best option in many cases, it shouldn’t be taken lightly. It must also be mentioned that veterinary medicine currently has no treatment for heartworm infection in cats. It has been found that cats generally do not tolerate the sudden release of dead heartworm debris into their bloodstream; therefore, the death of the worm also leads to the death of the cat. For this reason, heartworm-positive cats generally live the rest of their lives with heartworm.

dr Danielle Irving, DVM, is an Associate Veterinarian with the Richmond SPCA. To read her biography or that of our other bloggers, please click here. Before posting a comment, please read our Comment Policy. Please note that our commenting policy requires the use of a first and last name as a screen name.

Editor’s Note: The dogs pictured in this post underwent heartworm treatment while in the care of the Richmond SPCA. All have since been adopted into loving homes. If your dog needs heartworm treatment, monthly prevention, or general care at our affordable, full-service Susan M. Markel Veterinary Hospital, please click here to see if you and your pet qualify.

Heartworm disease is a very serious parasitic disease that can be fatal to your dog if not treated quickly.

This parasite is a worm that can grow up to 30 cm long and resides in the heart, lungs and associated blood vessels of an infected animal, where it continually reproduces. Heartworms have a lifespan of up to seven years, and it’s not uncommon for a heavily infested dog to have more than 150 worms in its body. By clogging these organs and blood vessels, the worms cause irreversible damage to them and other body systems. Eventually, if your dog is not treated, he is almost guaranteed to die of heart failure.

How is heartworm disease transmitted?

Heartworms are spread by mosquitoes. When a mosquito feeds on an animal with heartworms, they take part of the infection into their bodies in the form of microscopic baby worms known as microfilariae. They then pass these on to the next animal they bite. These microscopic larvae enter your dog’s bloodstream, where they travel to the heart, lungs, and associated blood vessels. It takes them about seven months to grow into adult heartworms, but once they do, they are able to reproduce. Because they have such a long lifespan, it is possible for a single heartworm to reproduce many times. Therefore, it is not surprising that the number of worms in a dog can increase rapidly.

If you have two dogs and only one has heartworm, there is no risk of them passing the disease on to your other pet. Although dogs are the natural host for heartworms, they can also infest cats, ferrets, foxes, and wolves.

prevention of heartworm disease

As a dedicated and compassionate owner, you want to do everything you can to protect your dog from this terrible disease, without exception. The good news is that heartworms are completely preventable.

Before you can start giving your dog any preventive medication, they must first be tested for heartworm. In fact, any veterinarian in Ponte Vedra Beach, FL will insist that heartworm testing is either part of your dog’s annual health exams or recommended as a result of a health exam. This is for two reasons. First, to make sure his prevention program is working, and second, because heartworm symptoms usually don’t show up until a large number are present in his body. Dogs are masters at hiding the fact that they are unwell and will continue to do so until they can no longer hide their symptoms. Likewise, heartworm symptoms usually don’t appear until after you’ve reached adulthood—about seven months after infection. If initial testing reveals that your dog has heartworm, treatment will be required before prevention can begin. However, if your dog is healthy, they can be treated with monthly medication to protect them from the disease.

Heartworm preventatives are generally given as a monthly dose and come in a variety of types. These include monthly pills you can hide in his food and topical treatments you apply to his skin that deter mosquitoes. There is also currently an injectable preventative that will protect your dog for up to six months. The most important thing to remember with any preventative measure is to stick to the dosing schedule recommended by your veterinarian. Even if you’re just a few days late, your canine pal is at risk of contracting heartworm. Make sure you carefully track the dates you take your choice of preventative and set reminders for the next dose. If you are unsure about which preventative to choose, consult your veterinarian.

Are heartworm preventatives expensive?

Everyone knows vet bills can be expensive, and many owners are concerned about the cost of preventative medication for their pets. First, we can assure you that preventing heartworm is far less expensive than treating the condition. In fact, a year’s supply of heartworm medication typically costs between $40 and $100 — less than the price of two fancy store-bought coffees a month for the whole year. When you consider that research has found the average cost to treat a dog for heartworm is between $400 and $1000, prevention definitely shows value for money. And, of course, without considering that you can save your dog a lot of unnecessary pain and suffering and irreversible damage to its health.

If you would like more information on heartworm prevention, our friendly and experienced veterinarians in Ponte Vedra Beach, FL are happy to help. Please contact us by calling Animal Care of Ponte Vedra located in Ponte Vedra Beach, FL at (904) 280-4544.

Warnings Your dog must be tested for heartworm infection before starting Heartgard.

Tips Store Heartgard at room temperature.

Heartgard is a once-a-month medication for dogs to help prevent heartworm. It comes in beef chewable tablets to make your dog want to eat it. Heartgard also has a Plus version that gives your dog extra protection against hookworm and roundworm. You can get Heartgard through your vet, or save a few bucks by purchasing it in Canada without a prescription.

Use Petdrugs.com (see Resources), one of Canada’s top sites for selling Heartgard. Shipping is a flat $6.95 if you live in the United States, but is free if you order the Heartgard over $99. Since your pet will need the Heartgard once a month, it makes sense to stock up and take advantage of free shipping.

Go to ABC Online Pharmacy (see Resources) if you don’t mind using Heartgard’s generic brand. This will save you a lot of money over the course of a year, and the generic brand has a reputation for being just as good as Heartgard. You don’t need a prescription as the company is based in Canada.

Buy Heartgard from Canada Drugs (see Resources) if you’re looking for a guarantee. Canada Drugs offers Heartgard with a price guarantee and a shipping guarantee. Even better, they have a no-hassle returns policy if you’re unsatisfied for any reason.

Check out Planet Drugs Direct (see Resources). This company offers more than just the product for sale without a prescription. They also contain information about the product, such as B. Instructions, precautions and side effects. It’s a great resource for learning everything you need to know about the product before you buy it. You can then purchase the product from Planet Drugs Direct.

Did you miss a dose of a medicine to prevent heartworm?

No panic! Here’s what to do if you miss a dose.

If you miss a dose of heartworm prevention medicine, there are a few things to consider before restarting your pet on heartworm prevention medicine.

However, if your pet has never been on heartworm prevention, it’s important that you learn how to get started right away. Heartworm disease was reported in all 50 states throughout the year. Monthly heartworm prevention can help your pet avoid this potentially fatal disease.

Why is it important to never miss a heartworm dose?

The American Heartworm Society has recommended year-round heartworm protection without missing a dose. A forgotten heartworm pill exposes your pet to infection, which can happen even in winter. Making monthly heartworm medication a part of your pet’s health plan will make it easier to remember. Of course mistakes happen and sometimes pet owners miss a dose. However, it may help you remember if you consider the following:

Heartworm disease is deadly…but preventable.

…but avoidable. Heartworm disease has been documented in all 50 states throughout the year.

Heartworm infection can cause varying degrees of cardiac and pulmonary pathologies in dogs and cats.

Heartworm disease can lead to a variety of symptoms, including exercise intolerance, coughing, possible heart failure, vomiting, lethargy, bloated abdomen, and in some cases, scary enough, sudden death.

Do I need to get my pet tested immediately if I miss a dose of heartworm?

Frequently, pet parents receive inappropriate information from both their friends and some veterinarians. It is not necessary to have a pet tested for heartworm immediately if they have not received heartworm medication in a month. This is because it takes at least 6 months for a pet to become heartworm positive when bitten by heartworm-carrying mosquitoes. This means that even if your pet became infected during the time you missed a dose of heartworm, the test results would not be that positive until 6 months after the initial infection.

What if the dose is just a few days late?

Most monthly heartworm medications have a safety factor of at least 15 days of protection if a dose is missed. This means that if you are just a week or two late, your pet is likely still within that protective window and is unlikely to become infected during that time. In this case, it would be okay to give your pet heartworm prevention medication as usual.

What if my pet missed a month of heartworm prevention?

The simplest answer for those who have missed a month of heartworm prevention is to dose right away and restart the monthly prevention schedule. A routine blood heartworm test is recommended at the time of an annual or biannual evaluation, along with a full wellness evaluation and/or immunizations and other laboratory tests as appropriate. While pet parents are encouraged to stick to their monthly heartworm prevention plan, accidentally missing a dose in these isolated circumstances poses no health risk or harm to their pets.

If there is no harm in skipping a dose, why can’t I give my pet heartworm prevention if I want to?

Pet parents should not choose their own monthly heartworm medication schedule. Irregular use of many medications, such as prescribed antibiotics and/or parasitic drugs, can be associated with the development of resistant strains of the parasite. It is difficult to predict when the heartworm transmission season will end or begin in many areas of the country. In fact, mosquitoes carrying heartworms have been seen in some areas of the country even during colder months.

Being a responsible parent means consistently providing your pet with the right health care, nutrition, and love. If you fail to protect your pet from heartworm, you’re unnecessarily exposing them to a deadly but preventable disease.

Interested in frequently asked questions about heartworm disease? Check out our heartworm disease FAQ resource.

Home » FAQs » Why Does Heartworm Treatment Cost So Much?

Many factors affect the costs associated with treating heartworm infection, including diagnostic tests, hospital stays, medications, and doctor visits. The current drug of choice is Immiticide and is difficult to obtain due to manufacturing problems and is therefore expensive. In addition, the protocol for treating heartworm disease is very laborious and has a long course.

Treatment can also be dangerous because heartworms reside in the heart and when killed go to the lungs where they must be slowly absorbed by the body (it is a closed system, unlike the elimination of intestinal worms, which, when killed, pass out into the feces). Heartworm prevention is a much better course of action as it is far less expensive than treating heartworm disease, is much safer and is virtually 100% effective when prevention is used correctly. For this reason, we recommend that you keep your pet on heartworm prevention year-round.

As winter descends in full force on New England, a growing number of dog owners are asking us if we recommend continuing heartworm prevention during the winter months. The short answer is yes. The American Heartworm Society recommends year-round heartworm prevention, and we agree. Want to learn more about heartworm disease and why it’s worth doing year-round heartworm prevention? Read on for the long answer to this big question!

How Do Dogs Get Heartworm Disease (And How Common Is It)?

Heartworm disease is caused by the bite of an infected mosquito, which deposits infective heartworm larvae into your dog’s bloodstream. Unless a preventative medication interferes with the development of heartworm disease by killing deposited larvae, these larvae will eventually grow into adult worms that can endanger your dog’s life if left untreated.

Although heartworm disease is generally less common in New England than in the southern United States, the rate of infection in a given region can vary widely from year to year. Infection rates can vary due to climate variability or due to changes in the number of wild animals that transmit the disease. In addition, heartworm disease is often spread when infected pets are unknowingly relocated from areas where heartworm disease is prevalent to areas previously at low risk. Of course, most dogs transported from high-risk areas will be tested for heartworm disease at some point prior to transport. However, because heartworms take six months to mature into adults, and the blood tests that are most commonly done look for adult female worms, it’s very likely that a dog will test negative but actually carry undetected heartworm disease. These dogs live in their new hometown for many months or even years before their heartworm disease is discovered and treated, increasing the risk of heartworm transmission in that area. Ultimately, with heartworm disease diagnosed in all 50 states, no place is risk-free.

Can heartworm disease be treated?

Heartworm disease can absolutely be treated if diagnosed on time, but it is a long and arduous process. Safely treating a dog for heartworm disease is not only a physically painful process for your dog, it also requires at least six months of strict exercise restriction. That means no running, jumping, chasing squirrels, or active playtime, and generally not fun at all! Ultimately, the best way to deal with heartworm disease is by preventing it from developing in the first place.

How do monthly heartworm preventatives work?

Unlike tick repellents, which kill ticks before they can complete the relatively slow process of transmitting tick-borne diseases to your dog, there is no way to kill mosquitoes before they start the incredibly fast process of depositing infective heartworm larvae into the bloodstream your dog have completed. Because mosquitoes are able to transmit heartworm larvae so quickly, heartworm preventatives work in reverse to kill any larvae your dog has been exposed to over the past month. The drug in your dog’s heartworm preventive is able to kill the heartworm larvae that have been transmitted through a mosquito bite as well as larvae that have reached the next stage of development in your dog’s body. However, once the larvae have developed into their adult form, monthly heartworm preventatives cannot effectively eliminate them. By administering preventatives every month of the year, we eliminate the possibility of immature larvae having time to develop into adults and cause heartworm infection.

Why continue heartworm prevention over the winter months?

Although heartworm disease is not as common in New England as it is in the southern United States, the risk of heartworm disease is increasing here in New England every year. Of course, the risk is higher in spring, summer, and early fall when mosquitoes are more active, but mosquitoes can also be found indoors long after cold weather has made outdoor living impossible. If a dog is bitten by an infected mosquito late in the season and then skips its heartworm preventive regimen during the winter months, it means that heartworm larvae are free to grow into adult worms that cannot be killed by your normal heartworm preventive regimen when you resume in the spring . As an added bonus, most heartworm preventatives contain additional medications to help control intestinal parasites like roundworms and hookworms. These parasites can be found in the soil all year round, which means your dog’s heartworm repellent is actually doing double duty. Even in an ideal world where your dog hasn’t been exposed to mosquitoes during cooler weather, his heartworm preventative is still working hard to keep him healthy. Additionally, since no preventative is 100% effective, and many pet owners (including those of us who are veterinarians) are not always careful to give our dog a heartworm preventive exactly once a month, we recommend giving your dog a yearly on to test for heartworm disease. even if they remain preventive throughout the year. However, because this annual heartworm test also looks for three of New England’s most common tick-borne diseases, it does the double duty of diagnosing conditions early and keeping your pet safe and healthy.

If you have a dog at home that is already heartworm negative, we strongly recommend that you do everything you can to keep it that way, which means doing heartworm prophylaxis once a month every month.

To a safe and healthy new year!

The CVH team

Heartworm prevention has become a standard of preventive care for pets in the United States. However, it is believed that more than 1 million pets in the US are heartworm positive and that number is growing.

Although some parts of the country are more affected than others, heartworm disease has been diagnosed in all 50 states.

You may need to have your dog treated for heartworm if:

If you have adopted a heartworm positive dog

If you missed your dog’s monthly dose of heartworm prevention

If you were unaware of heartworm disease until your dog tested positive

Regardless of the reason, if your dog has heartworm disease, here’s what you can expect to pay for each step from diagnosis to treatment.

1. The positive heartworm test

To be treated for heartworm, a dog must first test positive for the disease.

The most common heartworm tests can be performed right in your vet’s office, where results can be available in minutes. It is recommended that all dogs be tested for heartworm disease annually, even if they are on heartworm prevention.

A heartworm test can range from $35 to $75.

2. The confirmation test

If the practice test is positive, your vet will likely recommend a confirmatory test to confirm the positive test result.

Because no test is perfect — and heartworm treatment is expensive and can have significant side effects — your vet will want to be sure that treatment is necessary before proceeding.

Confirmation tests can vary and generally range in price from $20 to $40.

3. Determining the stage of heartworm disease

Once a dog has tested completely positive for heartworm disease, additional tests such as chest x-rays and sometimes echocardiography (an ultrasound of the heart) are done to assess the severity of the disease.

Staging helps the veterinarian assess the extent of damage already done by heartworms and determine specific treatment and follow-up regimens.

The cost of chest x-rays generally ranges from $125 to $200, and the cost of an echocardiogram can range from $500 to $1,000.

4. Initial treatment

Treatment generally begins the first day after a positive diagnosis of heartworm disease.

Initial treatment steps are taken to:

Adult heartworms weaken

Eliminate immature heartworms

Reduce the risks associated with melarsomin (the drug used to kill the adult heartworms)

Doxycycline and steroids

Before being given melarsomine, affected dogs are usually given doxycycline ($30 to $150), an antibiotic that helps weaken heartworms.

Dogs showing symptoms of illness, such as a cough or an intolerance to exercise, are generally started on a steroid ($10 to $40) to reduce inflammation.

The cost of doxycycline and steroids can vary depending on the size of your dog.

Preventive against heartworms

A prescription heartworm preventive is usually given on days 1 and 30 to kill heartworm larvae. After the first 30 days of treatment, there is a one-month waiting period. Heartworm tablets typically cost $6 to $18.

exercise limitation

It is important to note that once a dog is diagnosed with heartworm disease, restriction of movement should be implemented. The training constraint generally consists of strict crate rest.

5. Finishing stages

The final stages of heartworm treatment are designed to kill the adult heartworms.

This “adult extermination” treatment generally involves three injections of melarsomine, the drug that’s the mainstay of heartworm treatment.

On days 60, 90, and 91 of the treatment process, a melarsomine injection will be given deep into the lumbar muscles of your dog’s back. The dosage of melarsomin is weight dependent.

A round of steroids ($10 to $40) is generally prescribed for several weeks after each injection.

A series of melarsomine injections can cost anywhere from around $500 to $1,500, depending on your dog’s weight.

Strict movement restrictions should be continued for six to eight weeks after the last melarsomin injection.

6. Follow-up testing

About a month after the third melarsomin injection, your dog’s blood should be tested for the presence of microfilariae (a larval stage of heartworm that can be seen under a microscope). The microfilaria test costs $20 to $40.

If the microfilariae test is positive, the dog should continue heartworm prophylaxis for four weeks and then be retested.

A heartworm test ($35 to $75) is done about three months after the third melarsomine injection (one year after the initial diagnosis of heartworm disease). If positive, the dog should be treated with another round of doxycycline ($30 to $150) followed by two injections of melarsomine 24 hours apart ($500 to $1,000).

Complications that may prevent treatment with melarsomin

If your dog is very ill or debilitated from heartworm disease, your vet may not consider them a good candidate for melarsomine treatment.

Dogs severely affected by heartworm disease can develop a complication known as Caval’s Syndrome. Caval syndrome occurs when adult heartworms ingest so much of the right side of the heart that they block the blood vessels responsible for filling it with blood.

Caval syndrome is characterized by collapse, shock, and destruction of red blood cells. It’s usually fatal.

The only form of treatment is surgical removal of heartworm from the heart, which must be done in an emergency. This surgery can cost $3,000 to $6,000.

Cost-effectiveness of heartworm prevention vs. treatment

The cost of heartworm prevention is small compared to the cost of treating your dog for heartworm. Heartworm treatment is undoubtedly expensive. It is also uncomfortable for the dog, has significant side effects, and requires prolonged restriction of activity.

Treatment with melarsomine must be preceded by a series of diagnostic tests and treatments, which can cost anywhere from $100 to over $1,000 extra. This cost depends on the size of your dog, the severity of the condition, and your vet’s recommendations.

Then the cost of treating melarsomine heartworm can range from $500 to $1,500. If initial treatment doses are not fully effective, repeat treatment may be required, which can double these costs.

Fortunately, there are readily available, affordable, prescription medications that are highly effective in preventing heartworm disease. Heartworm prevention requires a prescription from your veterinarian and is generally given monthly as a pill that costs between $6 and $18 a month.

You can also opt for an injection. ProHeart 6 is a heartworm prevention shot that lasts six months ($50 to $150 per six months) and ProHeart 12 is a shot that is given annually ($75 to $350 per year).

It is generally recommended that heartworm medication be given year-round for the best possible prevention of this deadly parasite.

Sources:

The fee reference for veterinarians. 9th Edition, American Animal Hospital Association Press, 2015

www.aaha.org

www.heartwormsociety.org

www.veterinarypartner.vin.com

Featured Image: iStock.com/Morsa Images

Pet parents are always striving to make the best choice for their dogs. This is why parasite treatments are so important for heartworm prevention. With all the unique, high quality and stunning products available, it can be difficult to decide which is best for your dog. Two of the most popular products are Sentinel and Heartgard Plus. Both treatments offer safe and reliable protection, but there are many differences that set them apart. Read on for information that may help you choose the right formula for your dog.

What is the difference between Sentinel and Heartgard Plus?

These two products share a number of similarities. For starters, both are chewable, and both are formulated to be given to your dog on a monthly basis. Both formulas are safe for use in breeding or pregnant bitches, and Sentinel is also safe for nursing bitches. Both require a prescription from your veterinarian.

Both products are safe for use in puppies. Heartgard Plus can be used from 6 weeks of age, while Sentinel is safe from 4 weeks of age. Both products prevent heartworm disease and are both effective against roundworms and hookworms.

There are also some differences between these treatment options. Heartgard Plus contains Pyrantel Pamoate and Ivermectin, while Sentinel combines Lufenuron with Milbemycin Oxime. Sentinel provides additional protection against flea larvae and eggs, halting their development and ending the flea life cycle. It is not effective against existing infestations. Sentinel also fights whipworms.

How do I make a decision between Sentinel and Heartgard Plus?

To choose between these drugs, there are a few factors to consider. If you are planning to treat a puppy between the ages of 4 and 6 weeks, you should choose Sentinel. If your dog is nursing or needs protection from fleas, hookworm and whipworm, Sentinel is a great choice. You really can’t go wrong with any of these quality treatment options.

After becoming familiar with these products, it’s time to make an appointment with your veterinarian. With your veterinarian, you’ll weigh these options, discuss your dog’s medical history, and address any concerns you may have before choosing the right treatment for your dog. If you still have questions, contact Allivet Pharmacists for pet parenting advice!

Interceptor and Heartgard Plus are two of the most popular heartworm prevention brands, but is one a better choice?

Both are flavored tablets that, when given monthly, have been shown to prevent heartworm infections by killing the young worms before they reach the heart. There have been a few confirmed cases of heartworm resistant to both treatments, but fortunately these appear to be very rare at this time.

The two tablets have different active ingredients – Interceptor contains milbemycin oxime, while Heartgard Plus contains ivermectin and pyrantel. In addition to heartworms, both products also kill roundworms and hookworms. Interceptor also kills whipworms.

At a glance

Interceptor Contains milbemycin oxime.

Contains milbemycin oxime. FDA approved for heartworm prevention.

FDA approved for heartworm prevention. Must be given every month to be effective.

Must be given every month to be effective. Also suitable for roundworms, hookworms and whipworms.

Also suitable for roundworms, hookworms and whipworms. Resistant infections are possible but rare. Heartgard Plus Contains Ivermectin and Pyrantel.

Contains ivermectin and pyrantel. FDA approved for heartworm prevention.

FDA approved for heartworm prevention. Must be given every month to be effective.

Must be given every month to be effective. Also treatment for roundworms and hookworms.

Also treatment for roundworms and hookworms. Resistant infections are possible but rare.

Interceptor overview

Interceptor is a medication prescribed by veterinarians to prevent heartworm.

Heartworm is a serious parasite dogs can get from mosquito bites, which can lead to heart failure and death. Unfortunately, heartworm treatment is difficult and expensive when dogs have been infected for a period of time.

The best way to protect dogs from heartworm disease is to kill the young worms before they reach the heart. Not all dog dewormers kill heartworms, but Interceptor is one of those that can.

What is the active ingredient in Interceptor?

Interceptor contains milbemycin oxime. It belongs to the macrocyclic lactone family, which effectively kill young heartworms to prevent them from reaching the heart. It also treats hookworm, roundworm, and whipworm.

How often do I have to give Interceptor?

Interceptor must be administered once a month throughout the year. This will kill any young worms before they can reach your dog’s heart. Missing just a month of treatment can be enough for your dog to become infected.

Are there dogs that can’t have Interceptor?

Puppies must be over 4 weeks old and weigh over 1kg to be treated with Interceptor.

Dogs over 7 months of age should have a blood test before starting treatment with Interceptor to ensure they do not already have heartworm infection.

There are no known issues with Interceptor in any specific dog breed.

Can heartworms be resistant to Interceptor?

Unfortunately, some heartworms are now resistant to macrocyclic lactones like Interceptor. However, there is no evidence that worms are any more or less likely to be resistant to Interceptor compared to other brands.

The risk of your dog developing a resistant infection is very low, and heartworm is a serious illness, so this is no reason to stop giving your dog the medication.

All dogs at risk of heartworm should have annual blood tests to check for infection, even if they are receiving preventive treatment.

How much does Interceptor cost?

The price of Interceptor varies by region, so you’ll need to ask your veterinarian or pharmacy for the price. However, the cost is usually similar to other monthly heartworm preventatives, including Heartgard Plus.

Where can I buy Interceptor?

Interceptor is a prescription drug. You can buy it either directly from your veterinarian or by prescription from the pharmacy.

Do not buy Interceptor from anywhere that offers to sell it to you without a prescription as you may not be getting a safe or effective product.

Benefits Effective in preventing heartworm

Effective for preventing heartworm. Also for treating whipworm, roundworm and hookworm. Disadvantages Must be given every month to be effective

Must be administered every month to be effective. Does not treat tapeworms

Overview of Heartgard Plus

Heartgard Plus is another medication that veterinarians may prescribe for heartworm prevention. Dogs catch heartworms through mosquito bites, but Heartgard Plus works by killing the young worms before they can reach the heart.

What are the active ingredients in Heartgard Plus?

Heartgard Plus contains ivermectin and pyrantel. Ivermectin belongs to the macrocyclic lactone family, which are effective at killing young heartworms. Pyrantel treats roundworms and hookworms.

How often do I have to give Heartgard Plus?

Heartgard Plus needs to be administered once a month to keep your dog safe. You need to give it year round – even missing a monthly treatment can be enough for your dog to develop an infection.

Are there dogs that cannot get Heartgard Plus?

Puppies must be at least 6 weeks old before they can receive Heartgard Plus.

It’s important to make sure dogs are heartworm-free before starting a preventative medication like Heartgard Plus. Dogs over 7 months of age who have not received heartworm medication before should have a blood test performed prior to starting treatment with Heartgard Plus.

Some owners may be concerned about giving collies ivermectin (an ingredient in Heartgard Plus). This is due to a genetic mutation called MDR-1, which affects how sensitive dogs are to some medications. This mutation is usually rare, but is much more common in collie breeds, including Border Collies, Australian Sheepdogs, and Shelties.

At high doses, ivermectin is toxic to dogs with the MDR-1 mutation. However, the dose in Heartgard Plus is low and has been shown to be safe to give to collies with this mutation.

Can heartworms be resistant to Heartgard Plus?

It is possible for dogs to get heartworm infections that are resistant to Heartgard Plus, although fortunately this appears to be very rare. There is no evidence that worms are more likely to be resistant to Heartgard Plus than other heartworm preventatives currently available.

Luckily, these resistant infections are rare, so you should continue giving your dog a monthly preventive regimen. However, it is also advisable to have a blood test on your dog once a year to check that no heartworms have evaded prevention and grown up.

How much is Heartgard Plus?

Different retailers may price products in different ways, so you’ll need to ask your veterinarian or pharmacy. However, the cost is usually similar to other monthly heartworm preventatives, including Interceptor.

Where can I buy Heartgard Plus?

Heartgard Plus is only available by prescription. This means you can either buy it directly from your veterinarian or by prescription from a pharmacy.

Never buy Heartgard Plus from anywhere that is offering to sell it without a prescription as you cannot be sure if it is safe or effective. You should not use Heartgard Plus from a friend or neighbor, and you should not use it past the expiration date.

Benefits Effective in preventing heartworm

Effective in preventing heartworm. Also treats roundworm and hookworm. Disadvantages Must be administered every month to be effective

Must be given monthly to be effective Does not treat whipworm or tapeworm

What Users Say

To save you time, we took a look around to see what other customers think of Heartgard Plus and Interceptor, both in reviews and on pet forums!

Both products score in terms of palatability. Many customers say their dogs love the tasty tablets and take them as treats – no need to hide in their food! There is particular praise for the chewy texture of Heartgard Plus – some dogs who dislike hard tablets seem to prefer it.

Customers also seem to find both products effective – many have been using these tablets for years and their dogs have remained heartworm free! There are occasional reports of dogs getting heartworm while taking these drugs, but we know there are rare cases that are drug resistant – both Interceptor and Heartgard Plus can be affected. Infections can also occur if the medication is not given on time every month, even if the dose is just a day or two late.

Several reviewers also commend the fact that both tablets cover dogs for intestinal worms, although some are upset that Heartgard Plus doesn’t cover whipworm while Interceptor does.

There are some mentions of dogs getting stomach upset (vomiting and/or diarrhea) after using Interceptor or Heartgard Plus. However, many people whose dogs don’t get along with one found that the other suited them much better!

Conclusion

Both Interceptor and Heartgard Plus are FDA approved for heartworm prevention and reviews agree that they are both very effective products. Heartgard Plus may have a slight advantage in fussy dogs, but Interceptor provides protection against whipworm infections where Heartgard Plus does not. Neither treats tapeworms or offers protection against fleas, mites or ticks, so they should both be used in conjunction with other products as part of a thorough parasite prevention plan.

Overall, both Interceptor and Heartgard Plus are great choices for protecting your dog from the nasty disease heartworm.

Worm death can provoke a massive inflammatory response from the host, which is why a combination protocol with doxycycline, according to Dr. Herrin is “the safest way to treat” heartworm cases in dogs. By killing Wohlbachia spp, the endosymbiont within the microfilariae, doxycycline appears to reduce both heartworm-associated pathology and infectivity of D. immitis. Because the release of Wohlbachia triggers the host’s inflammatory response during worm death, pretreatment with doxycycline prior to administering adulticide therapy can significantly reduce inflammation. Once microfilariae lose the endosymbiont, they also lose their transmissibility when ingested by a mosquito. Therefore, doxycycline renders the microfilariae non-infectious and removes the patient as a reservoir for the population—an additional public health benefit.

Melarsomine is the only FDA-approved adulticide therapy for heartworm disease. The AHS-recommended protocol, considered safer and more effective than alternative protocols, consists of an initial injection followed by two injections a month later, 24 hours apart. If after the initial dose there is a significant inflammatory reaction or embolism, it is acceptable to wait more than a month for the last two injections. dr However, Herrin emphasized that the last two injections must be administered closely together as they offer a synergistic effect.

The American Heartworm Society (AHS) offers treatment guidelines for heartworm disease consisting of combination therapy with melarsomine, doxycycline, and a macrocyclic lactone. Brian Herrin, DVM, PhD, an assistant professor at Kansas State University College of Veterinary Medicine, discussed these recommendations, including the aspects most likely to confuse practitioners, in a recent class at the Fetch dvm360 conference.

Regardless of where you practice, chances are you’ve treated a pet for heartworm disease this year. Early diagnosis and early elimination of heartworm with adulticidal therapy give affected dogs the best chance at healthy living, but heartworm infection is devastating and damage can be lifelong.

The AHS recommends giving doxycycline for 28 days and then waiting a month before giving the first melarsomine injection. Many parasitologists and clinicians are now choosing to bridge the gap between treatments because waiting can affect patient compliance.

Macrocyclic lactone preventative

Use of a monthly preventative is also recommended throughout the course of treatment to control circulating microfilariae and remove the dog as a reservoir of infection for other animals. Preventative agents do not kill microfilariae, but rather stop the microfilariae from secreting certain proteins that help them hide from the host’s immune system.

dr Herrin cautioned that all currently available preventative options, including ivermectin, milbemycin oxime, moxidectin, and selamectin, are safe to use. In microfilaraemic dogs, an inflammatory reaction may occur following dosing, and patients with significant microfilaraemia should be pretreated with glucocorticoids and antihistamines prior to prophylactic treatment.

exercise limitation

Proper communication is critical when diagnosing heartworm, explained Dr. Mistress because it is important for patients to understand that the treatment is lengthy, can be painful and requires absolute compliance with the restriction of movement. Because exercise increases the risk of thromboembolism, strict cage rest is recommended, beginning with the first melarsomine injection and extending to six to eight weeks after the last injection. Leash walks are acceptable, but dogs should never be allowed to walk. (Check out these tips to help your dog overcome boredom while he’s cooped up during treatment.)

treatment alternatives

Some customers may find the AHS recommended protocol either too voluminous or too expensive. However, most alternative therapies are unacceptable. Reducing the melarsomine protocol to two doses is considered unsafe; “Slow-kill” methods using long-term macrocyclic lactone therapy do not effectively kill adult heartworm and may contribute to the development of resistant heartworm subpopulations.1,2

If owners cannot afford treatment at the time of diagnosis, Dr. Mistress to postpone melarsomine therapy but still initiate treatment with a preventative and doxycycline. This prevents further infection and removes the dog as a heartworm reservoir. After stopping treatment with melarsomin, owners need to understand that an untreated dog is at high risk for pulmonary thromboembolism and that exercise intolerance will inevitably develop as the disease progresses.

A recent study suggests that the combined use of a topical moxidectin+imidacloprid product (Advantage Multi, Bayer) and doxycycline can be an effective adulticidal treatment, particularly for early infections.3 The study showed that 30 days of doxycycline with 10 mg/kg followed by 10 months of moxidectin + imidacloprid in nonclinical dogs with stage 1 heartworm disease recommended treatment or the patient is not healthy enough to receive adult killer.

references

1. Geary TG, Bourguinat C, Prichard RK. Evidence of anthelmintic resistance to macrocyclic lactones in Dirofilaria immitis. Themes Companion Anim Med 2011;26:186-192.

2. Bowman DD. Heartworm, macrocyclic lactones, and the specter of resistance to prevention in the United States. Parasite Vectors 2012;5:138.

3. Savadelis MD, Ohmes CM, Hostetler JA, et al. Evaluation of parasitological findings in heartworm-infected beagle dogs treated with Advantage Multi® for dogs (10% imidacloprid + 2.5% moxidectin) and doxycycline. Parasite Vectors 2017;10:245.

dr Stilwell provides freelance medical writing and aquatic veterinary consulting services through her company, Seastar Communications and Consulting. In addition to her DVM from Auburn University, she has an MS in Fisheries and Aquatic Sciences and a PhD in Veterinary Medicine from the University of Florida.

What is the difference between Interceptor and Sentinel?

These two top products are similar in many ways. They’re both chewable, once-monthly prescription drugs with a delicious beef flavor. Both formulas contain milbemycin oxime as the active ingredient. Both products are safe to use in lactating, pregnant or pregnant bitches and can be given to puppies from 4 weeks of age (Interceptor should only be given to puppies weighing at least 2 pounds). Finally, both products are heartworm preventatives and both protect against whipworm, roundworm, and hookworm.

The main benefit of Interceptor is that it is safe for use in cats. Sentinel differs from Interceptor in that it contains a second active ingredient – lufenuron. This ingredient breaks the life cycle of fleas. It stops flea larvae and eggs from developing, but does not eliminate an existing flea infestation.

Key Takeaways on Interceptor vs. Sentinel

As you can see, there are a number of similarities that make these products equally effective in many ways. However, there are a few factors that can help you choose between the two. If you have a cat, Interceptor is the safe option for your feline family member. If you are looking for a broad spectrum product that will protect your dog from developing fleas, Sentinel is a great choice.

Your next step is to make an appointment with your veterinarian. Your veterinarian can weigh your decision and help you make the best choice for your individual pet based on his or her health history. He or she can also address your concerns and answer your questions. If you still have questions after leaving the vet’s office, contact Allivet Pharmacists for a Free Pet Parenting Consultation!