Myths & Facts About Heartworm Disease

Some of you may say to yourselves, "My dogs have never had heartworm disease--I don't need to give them a pill." 

Some people may even say, "Heartworm disease is a myth--it does not exist."   For those of you who choose to remain ignorant--DO NOT READ ON!  For those of you who want the best for their pets--PLEASE READ ON!

Myth: My dog will never get heartworms.

Fact: All dogs are susceptible to heartworm disease.  One bite from a mosquito carrying the heartworm larvae (immature stage) can infect your dog.

Myth: Even if my dog gets heartworm disease, he won't die from it.

Fact: Dogs and cats that have a single heartworm are at risk of sudden death especially cats.  These worms live in the heart and the large vessels of the heart and lungs causing a mechanical obstruction to blood flow.  In cats, a single heartworm can cause such an intense immune response that the cat often develops clinical signs identical to asthma.  These changes often cause irreversible damage.

Myth: It's not a big deal if my pet gets heartworm, I can just have her treated for the disease---it's all the same.

Fact: The treatment for heartworm disease in dogs involves injections of an arsenic compound---the only way to kill adult heartworms.  Obviously, the treatment is not without serious risks for the dog.  In cats, there is no treatment for heartworm disease.  Any arsenic compound is fatal to the cat, and the only way to remove heartworms in cats is to surgically remove them from the heart---also a very risky endeavor.  Bottom line---it is better (safer and cheaper!) to prevent the disease rather than to deal with the consequences of treatment, and for felines, there are no options once infected.

Myth: It is too hard to give my dog/cat a pill once a month, let alone remember to give the pill.

Fact: Heartworm disease is easy to prevent, and with many options for administration, there is really no excuse for not wanting to prevent a potentially life-threatening disease.

Heartworm preventives come in flavored tablets, chewable treats, and topical applications.  All medications have a monthly reminder system included in the package.  Rocky Shores Veterinary Hospital can also help you remember by sending you monthly reminders---just contact us and we can set that up for you!

For most of us, we chose our pets.  For one reason or another we welcomed them into our family.  Let's not forget that preventing them from getting sick is our responsibility as their "care-givers."

Feline Heartworms…A Hidden and Deadly Threat!  "HEARTWORMS LIKE US TOO!...meow!"

Most cat owners don’t worry about heartworm disease and fewer still use any sort of heartworm preventative.  But, as veterinary scientists continue to discover, feline heartworm disease has become a severe threat to our cat companions.  

Fred Thomas is religious about giving heartworm preventative to his three dogs.  On the first of every month, Fred breaks open a new package of medication and every dog gets their monthly treat.   Looking over at his cat, Fred grabs the kitty treats and tosses a few to the feline member of the pack.   What Fred doesn’t realize is that he is leaving his cat unprotected from a deadly killer.

Like Fred, most cat owners are unaware of this often fatal disease.  Heartworm disease was found in cats as early as the beginning of the 20th century, but few cat owners or veterinarians were concerned about it.    Recent studies have shown that 26% of cats from the Gulf Coast have signs of heartworm infection at some point in their lives and 10% have actual adult worms.  These prevalence rates are significantly higher than rates for Feline Leukemia or for the Feline Immunodeficiency Virus.  Yet, according to the American Heartworm Society, only about 5% of cat owners use any sort of heartworm preventative for their cats!  Like dogs, cats acquire the parasite from mosquitoes but this is when any similarity ends!  

Heartworms continually evolve to exist in their canine hosts, but cats are abnormal hosts and these heartworms will live stunted and shortened lives.   You might think that this is a good thing, but due to our cat’s strong immune systems, heartworms actually can cause more serious and severe disease than they do in dogs.   It is not unusual for a dog to live for years with 20, 30, or even 50 worms in their heart.   But a cat with a single heartworm can die suddenly, often with no apparent clinical signs whatsoever.  In addition, your “inside only” kitty is just as susceptible as the outdoor tomcat.

Upon infecting a cat, the heartworm larva will travel to the blood vessels of the heart and lungs, where it will grow to be about two inches long.   At this time, cats may exhibit respiratory symptoms that are often misdiagnosed as bronchitis or asthma.   Veterinary scientists studying heartworm disease in cats have given this stage of the disease a name:  Heartworm Associated Respiratory Disease, or HARD.  

As the heartworms mature, signs of their presence will often diminish.   In fact, evidence suggests that the live heartworms can actually suppress the cat’s immune function and the cat appears to tolerate the infection.   However, when the mature worms start dying, massive inflammation can occur, leading to acute lung injury and even sudden death.   Your cat can literally die within an hour!

So, what signs should you look for to keep your cat safe?   Cats with heartworms may exhibit difficulty breathing, coughing, vomiting, weight loss, sudden collapse, or even sudden death.  Because this disease can cause such a terrible outcome in a short period of time, your veterinarian should immediately examine any cat exhibiting these signs.  Tests are available to screen for heartworm disease, but again, unlike dogs, testing cats is a complex, often confusing, endeavor.  To make matters even worse, there is no effective or approved way of treating adult heartworms in cats.  So prevention is really the key!

And on that front there is good news!   Heartworm preventatives are available for cats and are as easy to give as the medications designed for dogs.   These preventives are available in both oral and topical formulations and Rocky Shores Veterinary Hospital can help you choose the right one for your pet.   We can also help you make sense of heartworm testing options for your cat.   Although the Heartworm Society does not mandate testing cats prior to using a preventative, it is recommended as a baseline for future reference.

Preventing heartworm disease in cats is only one step to helping our feline friends live long and healthy lives.   Twice yearly physical exams, blood tests and appropriate vaccinations can all do their part to insure your cat’s health.   To learn more about how heartworms can affect your cat, visit www.heartwormsociety.org