Although heartworm disease is a year-round problem, April is designated Heartworm Awareness Month, to draw attention to this dangerous parasitic infection. You have no doubt heard our Palm City Animal Medical Center team talk about the dangers of heartworm disease, but how much do you really know? Unfortunately, misinformation spreads like wildfire, and many pet owners are left wondering which statements they come across are factual. Let’s test your knowledge and separate fact from fiction about heartworm disease in pets. 

#1: Dogs acquire heartworms from other animals

Fact or fiction? Fiction. Unlike intestinal worms, which your dog can pick up from the environment or from contact with infected animals, heartworms are transmitted only by mosquitoes. Mosquitoes pick up heartworm larvae that circulate in the blood of infected animals when they feed. The larvae go through a critical development stage in the mosquito, and then can be passed on to other animals when the mosquito bites and deposits the larvae on their skin. The heartworm larvae enter the host’s body and migrate to the heart and lung vessels. The larval worms take approximately six months to complete their journey, mature, and begin to reproduce.

While an infected animal cannot directly pass heartworms to your pet, they can serve as an infection reservoir, meaning that mosquitoes can pick up heartworm larvae from them, and transmit the parasitic worms to your pet.

#2: Heartworm disease can be deadly

Fact or fiction? Fact. As heartworms reproduce, their numbers increase exponentially, and multiple generations can accumulate in the bloodstream, heart, and lungs. The worms’ presence causes significant inflammation in a pet’s body, which recognizes them as foreign invaders. The worms also obstruct normal blood flow, which leads to congestive heart failure. Without treatment, the disease will progress, and eventually cause death. 

#3: My cat cannot get heartworm disease

Fact or fiction? Fiction. While heartworms prefer canine hosts, including wild animals such as wolves, coyotes, and foxes, any mammal can become infected. If a mosquito carrying heartworm larvae bites your cat, the few worms that are transmitted can survive, but not replicate. Unfortunately, cats react intensely to the worms’ presence and only a few worms can cause significant inflammation. Heartworm-associated respiratory disease (HARD) causes asthma-like signs, such as coughing, wheezing, and difficulty breathing, in infected cats, who can also die suddenly.

#4: Protecting my pet from heartworm disease is easy

Fact or fiction? Fact. Fortunately, heartworm disease can be prevented with medications prescribed by our veterinarians. With a variety of options to choose from, keeping your pet heartworm-free is simple. Many pet owners opt for monthly chewables that contain a medication to rid their pet of any heartworm larvae that may have been transmitted over the past month, and topical products are available for pets with discerning palates. 

#5: Florida pets require year-round heartworm protection

Fact or fiction? Fact. Northern states have much colder winters that may effectively kill off the mosquito population, but our year-round sunshine also means year-round mosquito activity. Mosquitoes thrive in Florida’s hot, humid weather, and a strict prevention plan is required to keep your pet safe. The American Heartworm Society recommends year-round prevention for all pets, regardless of locale, but constant protection is especially important for Florida pets. 

#6: My pet does not need an annual heartworm test if they receive heartworm prevention

Fact or fiction? Fiction. Most heartworm medications work retroactively to kill larvae that may have been transmitted, but are effective against early development stages only. Once the larvae begin to mature, they are no longer susceptible. If you accidentally miss a dose, or your pet spits out their preventive behind the couch or vomits it in the yard, they are left vulnerable to infection. 

Since heartworms have such a lengthy life cycle, they can take a year or longer to accumulate to the numbers needed to cause clinical signs, such as coughing and lethargy. The disease becomes apparent only after progressing to a dangerous stage, and can cause life-long lung damage. Annual testing ensures your pet is parasite free, and detects infection early. 

#7: If my pet gets heartworm disease, they can easily be treated

Fact or fiction? Partial fact. Heartworm treatment is available for dogs, but is lengthy, costly, and harsh. A medication to kill adult worms is injected deep into the dog’s lumbar muscles. Several treatments spaced 30 days apart may be needed, along with additional medications to control inflammation and kill bacteria carried by the worms. Treatment typically lasts several months, and dogs must undergo strict exercise restriction to minimize the risk of dying worms lodging in the lung vessels and causing sudden death.

Unfortunately, no approved medication that kills adult heartworms is available for cats. Treatment focuses on reducing inflammation and managing clinical signs until the worms die on their own, which can take years. Since no curative treatment is available, prevention is particularly critical for your cat’s health.

Is your pet due for their annual heartworm test, or in need of preventive medication? Call Palm City Animal Medical Center to make this important appointment, and to keep your pet heartworm-free.