Heartworm – What you need to know

On a recent visit to the S.P.C.A (much, much more about that in posts to come), I noticed quite a few of the poor pups up for adoption had “heartworm positive” stamped on their information sheet. As I heard other prospective parents inquiring just what that meant for them and their future furbaby, I realized that  – despite being the dog expert that I am – I knew relatively little about this common ailment in dogs.

Heartworm (or Dirofilaria immitis if we are going to get scientific about it) is a parasite that spreads through mosquito bites.  The insane thing is…the baby heartworms (microfilariae) cannot grow up to be adult heartworms without passing through a mosquito.  In other words – it doesn’t spread directly from dog to cat or cat to cat…there must be a mosquito buzzing between the two to spread the parasite.  Ironically, once they are finished incubating inside the mosquito and are transmitted to the host, they reside in the pulmonary arterial system (or “around the lungs” for those of us who didn’t do so well in anatomy & physiology class.)  So heartworms actually end up affecting lungs more often than the heart.

One of the scariest things about heartworm is it is virtually impossible to detect without a blood test.  As the worms grow and spread inside the poor animal, they will begin to crowd the heart and lungs and most dogs will develop a cough.  Dogs will become lethargic –  not being able to exercise and play like normal.  Left untreated, heartworms are almost always lethal.

Heartworm is less common, but not unheard of, it cats.  Symptoms of the parasite in kitties are the similar to dogs (lethargy) along with loss of appetite, weight loss, vomiting, and diarrhea.  There is no treatment for heartworm for cats in the United States, but somehow cats seem to be able to rid themselves of in infection on their own.

Treatment for dogs is a drug, adulticide.  This is an “organic arsenical compound” that is administered through a series of injections and commonly requires hospitalization.

As we all know, preventing heartworms are a lot easier (and WAY cheaper) than treating them.  While some people think that it’s ok to sporadically administer preventative pills (thinking mosquitos don’t buzz around in the cold) or skip the pills all together (thinking they are in a “safe zone”) – this just isn’t the way to go.  Why take a risk with your beloved pooch?  Plus those pills prevent a lot more than just heartowrm…they help keep other intestinal parasites away.  AND – here is the gross part – those intestinal parasites can easily infect people.  (3 to 6 million peeps every year – yuck!)  There is your motivation right there!

The good news?  (As if there is any when you are talking about disgusting worms living inside adorable pooches!)  The S.P.C.A. has already started treatment for all their pups testing heartworm positive.  AND, I heard one knowledgeable volunteer lecturing, they will continue to provide treatment for their pups once they have been adopted out FREE!

Check out the American Heartworm Society for more information.