The news from the veterinarian hit them like a thunderbolt. Their dog Sparky had a heartworm infection. Suddenly, Sparky’s owners were faced with the prospect of a lengthy, painful and expensive treatment protocol, consisting of months of drugs and injections. The risk of complications was high, including potentially fatal blood clots to the lungs. The only thing riskier than treatment was not treating at all.
While Sparky may be a fictional case, his exact story is the sad and true one being lived out every day throughout the country. Spread through a single, unlucky mosquito bite, this was once considered a disease primarily of the south. Changing temperature patterns, however, have propagated its spread to every US state except Alaska. Urban development has created infectious hot spots through thermal heating and radiation of concrete structures such as buildings and parking lots, effectively lengthening the transmission season and increasing risk even to urban “apartment” pets.
Because this disease spreads through a mosquito bite and not dog-to-dog, ALL dogs are at risk. Once the mosquito bites, microscopic precursors grow through several larval stages into worms. By four months, they have grown into foot-long adult worms living in and near the dog’s heart. Here, they reproduce, creating new worms that increasingly clog the heart and damage the liver and kidneys as well.
Click here to view photos that show heartworms in the heart. Warning! They are graphic images!
Symptoms may be almost imperceptible at first. Ultimately, coughing and fatigue occur. This progresses to trouble breathing. If diagnosed early enough, nonsurgical treatment may be an option, but it is not without considerable risk, including three deep muscle injections in an inpatient setting with an arsenic-containing drug called melarsomine. Untreated heartworm disease can eventually result in an acute episode called caval syndrome in which the worm burden is so heavy that the only option is an immediate, lifesaving but risky surgery. In all cases, dogs with untreated heartworm disease will succumb to the infection.
Here at North Penn Animal Hospital, we have seen three positive cases of endemic heartworm disease last month alone. These three dogs never spent any part of their lives outside Pennsylvania and got that unlucky mosquito bite in their own backyard.
The good news? This does not have to be your story. Easy, highly effective and affordable prevention is available. Unlike treatment, prevention is effective, painless, safe, and far less expensive. Interceptor Plus or Simparica Trio given monthly all year will not only prevent heartworm, but also other parasites that can live in the intestines, some of which can in turn infect people. Cats can also get heartworm. And while there is no treatment for feline heartworm disease, there are effective spot-on products that prevent it such as Revolution Plus.
The American Heartworm Society recommends yearly testing which can be done with a small blood sample in eight minutes right there at the appointment. Testing is also recommended anytime a monthly dose is missed. A Heartworm prevention product used regularly in conjunction with flea and tick prevention is one of the safest and surest ways to ensure your pet’s health.
Written by NPAH Relief Veterinarian, Lee Friedman, VMD