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Southside Animal Hospital

April is National Heartworm Awareness Month – Is Your Pet Protected?

dog with tongue out

Are you thinking, really, a worm that lives in the heart? Well, it’s true – and they do exist. And, unfortunately, we have heartworm infection in both dogs and cats here in San Angelo and the Concho Valley. Despite the recent drought, there are still multiple larger local bodies of water where mosquitoes can live and transmit heartworms.

So what do mosquitoes have to do with heartworms?

A lot! Mosquitoes are a required part of the heartworm life cycle. When a mosquito bites a dog with a heartworm infection, it picks up baby heartworms (microfilaria) that are circulating in the bloodstream. That baby heartworm then matures in the mosquito. When the same mosquito bites another dog or cat, heartworms are transmitted to that pet. Then it takes about 6 months for that immature heartworm to migrate from the blood, through other organs, and finally to the lungs as an adult. As the number of worms in the blood vessels (arteries) of the lungs increases, the worms move into the heart.

Why does it matter if my dog or cat has heartworms?

Heartworm infection is a life-threatening infection. The parasites damage the lining of the blood vessels in the lungs causing inflammation and thickening of vessels. As the number of worms in the body increase, they begin to damage the heart. In dogs, lethargy, decreased appetite, cough, and difficulty breathing can develop. Eventually, right-sided heart failure can develop. Unfortunately, cats can suddenly die without showing any other signs in reaction to a heartworm dying naturally. Cats can also experience vomiting, gagging, difficulty breathing, and weight loss.

How can I prevent my pet from developing heartworm infection?

There are three different options for heartworm prevention in dogs: monthly oral preventatives, monthly topical preventatives, and a twice-yearly injection. All of these preventatives act to kill some of the immature stages of heartworms before they develop into adults. Most also kill circulating baby heartworms which can cause an allergic reaction. So it is VERY important that your dog be tested for heartworms before starting prevention. Please call to discuss prevention options in more detail. In cats, there are only monthly topical preventatives or monthly oral preventatives (not as widely used).

Year-round prevention is MUCH better than just giving prevention when you think mosquitoes are out. And, mosquitoes CAN get indoors – so even dogs and cats that spend most of their time inside need to be on prevention year round.

What if my pet develops a heartworm infection?

Treatment to kill adult heartworms in dogs is available, but it is not without risks. The medicine is injected into the dog’s back muscles in a series of 3 treatments. As the adult worms are killed, your pet’s body has to breakdown the worms. If your dog is active or exercising during this process, they can develop blockages in the blood flow to their lungs, and sudden respiratory difficulty that is an emergency. However, the longer worms stay in your dog’s heart and lungs, the more damage they do.

Currently there is no treatment available for heartworm infection in cats. So, prevention is key!

All animals with heartworms should also be on a preventative medication to prevent re-infection.

Please call our office at (325) 653-0113 today to schedule an appointment to test your animal and start or restart heartworm prevention if your pet is not currently protected!