Your pet holds a special spot in your heart as a beloved furry family member, but what happens when a deadly parasite sneaks close to their heart? Heartworms are an insidious parasite that set up residence in and around your pet’s heart and lungs, mostly in the major blood vessels. To keep your four-legged friend safe from these parasites, learn how your pet is at risk, heartworm disease signs, and the best prevention options.

What is heartworm disease in pets?

The name “heartworm” is a bit misleading, since these parasites actually live in the heart only when a pet is heavily infected. Nevertheless, heartworms put a serious strain on the heart and create intense reactions in the surrounding blood vessels—mostly the pulmonary vessels that lead from the heart to the lungs—that can permanently damage your pet’s circulatory system. And, unlike other “worms,” you can’t see this one in your pet’s feces, because heartworms are not intestinal, like roundworms, hookworms, tapeworms, and whipworms.  

How is heartworm disease transmitted to pets?

Heartworm larvae are transmitted when an infected mosquito bites your pet. The larvae wriggle into the bite wound and travel through your pet’s body to reach their ideal location—the major blood vessels surrounding the heart and lungs. During their journey, the larvae slowly grow to their adult length, which can be up to 12 inches for canine heartworms. After six months, the immature heartworms grow to adulthood and begin reproducing. These heartworm larvae are then capable of infecting another pet. While heartworms cannot be directly transmitted through pet-to-pet contact, one infected pet can spread heartworm larvae to mosquitoes in your area, which can then infect your pet. 

What are heartworm disease signs in pets?

Heartworm disease signs differ in dogs and cats. In dogs, the most common sign is a dry, hacking cough that progressively worsens. Additional signs include exercise intolerance, fatigue, and inappetence. If the disease progresses without treatment, the worm burden can create cardiac issues that can cause a swollen, fluid-filled abdomen. 

In cats, heartworm disease most commonly appears with similar signs to feline asthma. An infected cat may cough, wheeze, or have difficulty breathing. They may also vomit, have problems walking, suffer from seizures, or die without warning. Since cats are not the ideal heartworm host, they can experience a serious reaction to a single worm. In cats, heartworms can cause severe inflammatory reactions before they reach adulthood, and only one adult heartworm can be suddenly fatal.

How is heartworm disease in pets diagnosed?

Heartworm disease can be diagnosed in pets during their annual wellness visit, or if they are displaying illness signs. A few drops of blood is all that is needed for an in-hospital test, where results can be gathered in under 10 minutes. However, testing can be tricky, as the results can be false-negative if the heartworms are less than 6 months old, all male, or too few. The common in-hospital test detects the antigen of only adult female heartworms, so an accurate test result requires the right conditions. Fortunately, multiple outside laboratory tests can help diagnose heartworm disease, or confirm test results.

How is heartworm disease treated?

Heartworm disease is much more difficult to treat than to prevent. In dogs, a series of injections are administered deep into the pet’s lumbar muscles, which can be painful. Injections may be administered a month apart, and during this time, the dog must be exercise-restricted to prevent the dying worms from forming clots. In some cases, a dog undergoing heartworm treatment must be kept inactive for up to 12 weeks, which can be extremely difficult for both the pet and the owner.

No approved heartworm treatment is available for cats, whose only option is supportive care based on their signs.

How can I prevent heartworm disease in my pet?

Preventing heartworm disease in pets is simple—you administer a heartworm preventive in topical, oral, or injectable form to your furry pal, on schedule, to avoid any lapses in protection. Your Stone Ridge veterinarian can help you decide on the best prevention choice for your pet.

Although heartworm prevention is not required for our boarding services, like flea and tick prevention, you should protect your pet from all three major parasites. This is made easy for you, because products that protect your furry pal against heartworms, fleas, and ticks in a single product are available. Ask our team for more information about parasite prevention options for your pet.