Heartworm is a parasite that can infect both dogs and cats.  It is a vector-borne disease, meaning that heartworm must travel through another parasite or vector.  In the case of heartworm infection, that vector is the mosquito, and for this reason, heartworm infection does not occur through direct contact between animals.  

Historically, heartworm has not been very prevalent in the Pacific Northwest and has always been a much bigger issue in the Southeast, New England, Texas, and even California.  But this has been changing over the last decade.  Although rates of infection in Washington are still somewhat low in comparison to the above regions, the number of positive cases is steadily increasing, a result of various factors:

• Warmer temperatures promote a longer “mosquito season.”
• Many Washingtonians adopt pets from heartworm-endemic areas like Texas, Mexico, Louisiana, and California, which brings more heartworm to our area.
• Because so many Americans consider their pets family members or service animals, a lot more pet owners travel with their pets, including our animal-loving soldiers right here at JBLM, all of whom travel through regions of the United States with a heavy heartworm burden.
• Rescue pets, military pets, humans traveling with service animals, and purebred purchased animals from all around the country join us in Washington, and many of them – even the puppies – carry heartworm infections with them.

Each of these factors is likely playing a role in Washington’s heartworm rates being on the rise.  Remember, being an indoor-only animal, staying in a fenced backyard, and living in a gated community DO NOT protect your animal from mosquito bites! 

Heartworm Disease is very serious.  The adult worms take up residence in the heart and pulmonary arteries, interfering with the function of heart and ultimately resulting in heart failure.  Yes, there are literally worms living in the animal’s heart.  It is a treatable disease for dogs but the damage that is done to the heart is often irreversible.  Successful outcome depends on how long the animal has been infected, how many adult worms are present, and how much damage to the heart has already occurred.  Treatment is costly and time-consuming, is only available for dogs, and it has its own very serious risks associated with it.  Although infection in cats is mercifully less common, for them there is no treatment at all.  Prevention, therefore, is key. 

In any case, ten years ago many Washington veterinarians felt that recommending heartworm prevention was unnecessary for pets who never traveled out-of-state.  The focus, however, has shifted in recent years because rates of infection are very much on the rise.  We will say it again, at Pinehurst it’s about preventive care.  We would rather take a proactive stance and focus on preventing heartworm disease in your animal overtaking a reactive stance and treating it, as prevention is so much safer for our patients. Treatment is so easy, so safe, and comes in the form of an annual injection (dogs only) that can be administered with his or her wellness exam, or a once a month treatment (dogs and cats) that also simultaneously treats for fleas and ticks.  An annual heartworm test is required.  Please ask one of our knowledgeable staff members about heartworm prevention right away.