Heartworm disease is a life-threatening but preventable condition that affects dogs and cats across the United States. Despite increased awareness about the disease and better access to safe and effective prevention, heartworm infection rates in pets continue to climb.  

The Pierson Pet Hospital team is dedicated to client education and empowerment. We believe that the more you are informed about pet health topics, the better you can protect your four-legged friend. Here are seven fast facts every dog and cat owner should know about heartworm disease in pets.

#1: Heartworm disease is a real and present threat to pet health

According to the American Heartworm Society, more than one million U.S. pets are suffering from heartworm disease. Once limited to warmer climates in the Southeast, this life-threatening disease now has spread to non-endemic areas and has been confirmed in all 50 states. 

Last year in Michigan, 1 in 200 dogs were diagnosed with heartworm disease—not including countless untested dogs. And, because cats are equally susceptible but not routinely screened for heartworm disease, we assume their infection rates are similar, if not higher.

#2: Heartworm disease is transmitted by infected mosquitoes

One reason why heartworm disease is so pervasive is because transmission occurs via the mosquito—a proliferative and pesky parasite that can reproduce rapidly, makes its home in any moderately warm climate, sneaks indoors through open windows, and overwinters in garages, basements, and other similar accommodations.

And, mosquitoes don’t merely infect pets—they play a crucial role in the heartworm life cycle. When mosquitoes bite a heartworm-positive pet, they ingest the infective larvae, which pass through two maturation stages, and then migrate back to the mosquito’s mouth parts to infect another pet.

#3: Early heartworm disease signs in pets are mild or nonexistent

Like the mosquito, heartworm disease is a sneaky threat. Early disease signs usually do not appear for months, and are often subtle and nonspecific in dogs (e.g., cough, reluctance to exercise, lethargy). Infected cats may be completely asymptomatic or be misdiagnosed with asthma. Unfortunately, by the time signs appear, heartworm disease is already on its warpath through the cardiovascular system, triggering harmful inflammation, damaging major lung vessels, congesting heart chambers, and obstructing normal blood flow.

#4: Treatment is costly and prolonged for dogs, unavailable for cats

Once clinical signs are present, killing the adult worms is the only veterinary treatment for the pet’s survival. Sadly, no safe treatment is currently available for cats, and they can only receive supportive care that eases their discomfort. However, cat infections are small (e.g., one to two adult worms), so some cats outlive their disease.

Treatment for dogs requires antibiotics, deep, intramuscular injections that must be administered by a veterinary professional, and then prolonged activity restriction. Dogs must be kept calm and relaxed to prevent dead or dying worms from creating life-threatening blockages (i.e., emboli) as they travel out of circulation.

You don’t gamble with your beloved pet’s health, so don’t bet against heartworm disease. Talk to your veterinarian about year-round prevention.

#5: Year-round prevention is your pet’s best defense

When it comes to heartworm disease, an ounce of prevention truly is worth a pound of cure. Heartworm preventives come in the form of a monthly pill, topical application, or a twice-yearly injection, and provide reliable and economical protection against heartworm disease transmission by eliminating microfilariae (i.e., the juvenile heartworms that mosquitoes inject under your pet’s skin).

By stopping heartworm disease in its tracks, preventives block disease progression and its harmful side effects. But, preventives must be given year-round, including during winter months, to be effective. Pausing your pet’s prevention is strongly discouraged for several reasons, including:

  • Mosquitoes can reemerge on mild winter days. 
  • Owners often forget to resume their pet’s preventives after a break.
  • One missed or forgotten dose can leave your pet vulnerable to heartworm disease.
Indoor-only pets should also receive heartworm preventives, as mosquitoes can slip through open doors or broken window screens.

#6: Annual heartworm disease screenings can identify early infection in dogs

Heartworm disease screenings (i.e., heartworm tests) are standard in our yearly canine wellness visits. These simple blood tests detect heartworm antibodies produced by adult worms and can indicate hidden infection.

Heartworm tests are a key piece of your dog’s prevention plan, along with year-round preventives. Heartworm testing ensures your pet’s preventives are working appropriately and identifies early infections because of a missed or forgotten dose, which allows us to treat your pet before they are permanently damaged.

For pets on heartworm prevention, testing also provides peace-of-mind against rare—but possible—breakthrough infections. 

#7: Wellness plans are a convenient way to protect your pet from heartworm disease

Fortunately, for all the bad things about heartworm disease, protecting your pet is relatively simple. Pierson Pet Hospital’s wellness plans make safeguarding your pet from heartworms at every life stage easy. Each plan—from puppy and kitten to adult and senior dogs and cats—includes species and age-specific care and a 12-month supply of preventives.’

Heartworm disease is a nasty nemesis—but your pet doesn’t have to be its next victim. Protect your four-legged friend from the heartbreak of heartworm disease by scheduling an appointment at Pierson Pet Hospital.