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Heartworm Disease: A Hidden Killer
Photo courtesy: Hillary Winchester Photography

Heartworm Disease: A Hidden Killer

Photo courtesy: Hillary Winchester Photography

AUBURN, Alabama — Many household pets in the United Stated suffer from a serious and potentially fatal disease, especially in the southeast.

Heartworm disease affects mainly dogs and cats. Mature heartworms can damage an animal’s heart, lungs and arteries.

“Once heartworms get into a dog, cat or ferret, the larvae can mature into adults, which affect the heart, lungs and the vascular system, causing potentially life-threatening cardiovascular disease,”  Alabama Extension veterinarian Dr. Soren Rodning said. Rodning is also an associate professor in the Department of Animal Sciences at Auburn University.

Mosquitos spread the disease. Once an infected mosquito bites an animal, the larvae slowly develop into adult heartworms.

Mosquitos pick up the heartworm larvae from an infected animal. Heartworms live in many mammal species. Infected animals that live near urban areas such as foxes and coyotes, are crucial to the spread of heartworm disease.

During the early stages of heartworm disease, animals rarely show any symptoms. Once the disease progresses, animals start to show symptoms. Symptoms include chronic coughing, unwillingness to exercise, fatigue, reduced appetite and weight loss. Animals can also experience swelling in their belly due to excess fluid.

“Probably the most common complaint that I’ve seen pet owners notice is dogs that have a chronic cough,” said Rodning. “This can sometimes be mistaken for a lot of other things that can make a dog cough. The one thing that sets it apart is that it’ll last for months, potentially until the dog is diagnosed and treated.”

Large numbers of heartworms can accumulate in dogs without testing and treatment. This can cause caval syndrome, a life-threatening form of cardiovascular collapse. This can cause blockages of blood flow within the heart. Few dogs survive without immediate medical attention.

While heartworms can live in cats, most cannot reach adult stage. However, they can still cause damage and cats should be tested annually and kept on heartworm preventative.

Photo courtesy: Hillary Winchester Photography

Because of the absence of symptoms in the early stages and the risk for both outdoor and indoor pets, the American Heartworm Society suggests everyone get their pets tested every 12 months. They also suggest everyone give their pets a heartworm preventative medicine 12 months a year.

“Even if the animal is on heartworm preventative every month, it’s still important to have pets tested every year,” Rodning said. “That way you know if the preventative is working and that your pets haven’t be infected with heartworms. Heartworm preventatives are very effective, but not always 100 percent effective. Dogs can spit out their monthly heartworm preventative tablets without the owner even realizing it.”

April 2017 is Heartworm Awareness Month. For more information about heartworm disease, visit the American Heartworm Society’s website.


The dogs featured in this article are heartworm positive and available for adoption at Lee County Humane Society.

About Rachael Barnes