Heartworms: Prevention is the Best Medicine

April showers bring May flowers… and, unfortunately, the onset of heartworm season in much of the country. That’s why it’s National Heartworm Awareness Month. Heartworm can be fatal and it is very difficult – and expensive — to treat so prevention is always your best bet.  Here’s what you need to know.

What types of animals get heartworm?

Many mammals get heartworm including dogs and cats. The disease is rare in humans.  Note that heartworm susceptibility, diagnosis, and treatment are different for dogs and cats.

Where are heartworms prevalent?

Heartworm can be found throughout the U.S. but it’s more prevalent in the Midwest and Southeast because the parasite flourishes in tropical and subtropical climates.  Check this map to see how common it is in your area:


Heartworm Incidence Map Courtesy of Heartwormsociety.org

Heartworm Incidence Map Courtesy of the American Heartworm Society


How do pets get heartworms?

The parasitic nematode Dirofilaria immitis, commonly called heartworm, is transmitted via mosquitoes. When a mosquito infected with heartworm bites your pet it can transmit heartworm larvae into your pet’s bloodstream. Once inside your pet, the larvae continue to develop over the course of about six months. They make their way to the heart or lungs where they mature and reproduce. Adult worms live for years, can grow to more that 12 inches long and cause blockages in the heart and lungs and damage to arteries.

What are the symptoms of heartworm disease?

Often there are no obvious initial symptoms when your pet is infected with heartworm. Once the disease has progressed, dogs may begin to cough, experience shortness of breath, and be unwilling to exercise. Symptoms in cats are non-specific – like coughing or rapid breathing — and are often mistaken for other medical problems. Some pets show no symptoms until they collapse or faint due to “caval syndrome,” at which stage the body is so infected that treatment and recovery are unlikely.

Why is heartworm prevention so important?

Once a pet has been bitten by an infected mosquito it takes up to six months for the heartworms to show up on tests. By then damage has been done and treatment regimens are costly, complicated and aren’t always effective. Your best bet is to prevent this disease rather than attempt to treat it.

We stock many heartworm preventative treatments for dogs and cats.  Choose from monthly oral medications or topical treatments — both types are effective, convenient, and affordable. Talk to your veterinarian about which treatment is best for your pet and your area.

Want to learn more about heartworm and how to prevent it? Listen to Dr Rubin’s short podcast presented by the American Heartworm Society.

Here’s to a happy, healthy spring for your pet!