No pet owner should mess around with heartworm disease that, at worst, can be fatal, but is always a serious condition, because the heartworms traveling through your pet’s body can cause massive amounts of permanent damage. Fortunately, you can prevent your pet from heartworm disease and keep them safe by administering year-round heartworm prevention.

While we normally wouldn’t recommend playing games with your pet’s heart, try your hand at this fact-or-fiction quiz to test your knowledge about heartworm disease and prevention.

Fact or fiction?: Heartworm disease is transmitted like other “worm” diseases—through contaminated feces

Fiction: Many “worm” infections you may have heard about, like roundworm, whipworms, and hookworms, are transmitted via contact—typically ingestion—with contaminated feces. However, heartworm disease is not an intestinal parasitic disease, so the transmission method is different. While worms still develop in your pet, they must be transmitted through the bite of an infected mosquito, not through contact with feces. Once an infected mosquito bites your pet and transmits the immature heartworm larvae (i.e., microfilariae) into your pet’s skin, the larvae take five to six months to achieve adulthood and begin reproducing. Then, another mosquito takes a meal from your pet, and inadvertently becomes infected with microfilariae, and the life cycle continues anew.

Fact or fiction?: Any mammal can get heartworm disease

Fact: While dogs are commonly thought of as heartworm disease victims, cats and ferrets can also be infected. In fact, any mammal, from seals to people, can develop heartworm disease. However, heartworms prefer dogs and wild canines as their hosts, so heartworms rarely reach adulthood in other species, including cats. However, only a few worms can damage the cat’s heart, lungs, and surrounding blood vessels, despite their highly effective immune response that typically eradicates heartworms before they become adults.

Fact or fiction?: Only pets who go outside need heartworm prevention

Fiction: If you’ve never seen a mosquito, fly, or other insect in your home, you must be living in a bubble. Mosquitoes are sneaky pests that slip in through open doors or holes in window screens, and once inside, seek out their next meal, which will likely be your pet. This means no pet is safe, including your indoor-only cat who has never frolicked in your yard.

Fact or fiction?: Heartworm disease is not obvious in pets

Fact: While late-stage heartworm disease can be recognized by a fluid-filled abdomen caused by heart failure, you likely won’t know early that your dog has heartworm disease, because they will likely show no illness signs in the early stages. However, as the disease progresses, dogs may exhibit a mild, persistent cough, and a reluctance to exercise, followed by a worsening cough, and extreme fatigue after any physical activity. 

Cats typically develop signs similar to asthma, so they may cough, have difficulty breathing, or breathe rapidly. However, they may also have difficulty walking, vomit, develop seizures, or suddenly collapse or die. With such vague signs, early detection, diagnosis, and treatment is essential for a positive outcome.

Fact or fiction?: Heartworm disease can be tricky to diagnose

Fact: Although an in-hospital blood test using a few drops of blood can quickly diagnose heartworm disease, false-negative results are possible. Standard, in-hospital tests generally test for the adult female heartworm antigen, so if the worms are immature, all male, or too few in number, the result will be a false negative. Because of the potential for false-negative results, annual testing is recommended to ensure no inaccuracies.

Fact or fiction?: Treating heartworm disease is simple

Fiction: Heartworm disease is not only challenging to diagnose, but also difficult to treat. If your dog has been diagnosed with heartworm disease, they will need to undergo a series of painful injections administered deep into their back muscles. During the treatment process, your dog will need to be leash-walked outside for short bathroom breaks, and then confined to prevent too much physical activity. If your dog is too active, they can experience adverse side effects, such as a blockage formed by the dying worms. This period of exercise restriction can last two months or more.

For cats, no heartworm disease treatment is available, so treatment instead focuses on managing clinical signs.

Fact or fiction?: Protecting pets against heartworm disease is easy

Fact: Fortunately, protecting pets against heartworm disease is much easier than treatment. Administration of a monthly heartworm prevention product, whether in chewable tablet or topical liquid form, will keep your four-legged friend safe from heartworm disease, in addition to protecting them against intestinal parasites. Some heartworm preventives also will protect against fleas and ticks.

If you’d like to uncover more facts about heartworm disease, contact our MetroPet Veterinary Clinic team. While you’re here, stock up on more heartworm prevention products, to keep your furry pal safe.