Carolinas Animal Hospital

Heartworm Disease Is Fatal: What You Need to Know

Heartworm disease is fatal to dogs and cats. It causes lung disease, heart failure, and damage to other organs as a result of having worms that are a foot long living inside the heart, lungs, and blood vessels. Can you imagine having dozens of them thriving inside your heart and lungs? They gradually cause more and more damage, and during this time, the affected pet can also contribute to the spread of heartworms to other animals by carrying them in their blood. The good news is it is preventable! Let’s take a closer look at what they are, how they are transmitted, and why you need to protect your dog or cat from heartworm disease.

How are heartworms transmitted?

Mosquitoes are to blame for the transmission of heartworms. When they ingest the blood of an affected animal, they take in microfilariae, microscopic baby heartworms. In ten to 14 days, a microfilaria will grow enough to be able to infest the next host that the mosquito bites. After taking up residence in their new host, it takes up to six months for the heartworms to mature into adults, but they can begin causing damage before maturation.

All 50 states in the U.S. have had reported cases, but the southeastern region has especially high rates of heartworm disease every year. This is due in part to being a warm, humid area where mosquitoes thrive for a longer portion of the year. Charlotte, NC is right in the midst of the high-risk area for dogs and cats. Animals can even have heartworms transmitted to them multiple times due to this, which causes a substantial increase in the number of worms very quickly.

Photo source: American Heartworm Society

Photo source: American Heartworm Society

What are the symptoms of heartworm disease?

In the early stages, pets may not show any symptoms of infestation or disease while the worms are still young or not yet in large quantity. Despite a lack of outward symptoms, even young worms are already causing damage. Eventually, in cats, it’s common to see symptoms that resemble asthma, coughing, lack of appetite, vomiting, weight loss, and occasionally, fainting, seizures, or a distended abdomen from fluid build-up produced by the failing heart and lungs.

In dogs, symptoms are often most pronounced in active dogs because the worms hinder the heart and lungs’ ability to function properly in general, but especially during exercise. Dogs will often display fatigue after even mild exercise, a persistent cough, decreased appetite, weight loss, distended belly, and eventually also cardiovascular collapse called caval syndrome. Caval syndrome presents with labored breathing, pale gums from lack of blood flow in the body, and bloody urine. It requires emergency surgery to removes large numbers of heartworms to save the dog’s life.

What you can do!

Heartworm disease is terrible, but we have tools to help our dogs and cats to maintain their quality of life by choosing testing and prevention as our primary defense. In the event of heartworm infestation and disease, treatment might be possible depending on your pet. Check out our upcoming article about heartworm treatment and prevention to learn more!


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