April is Heartworm Awareness Month!

posted: by: Staff Tags: "Clinic Specials" "News" 

What is heartworm disease?

Heartworm (Dirofilaria immitis) is a fairly large worm - up to 14 inches long - that, in adulthood, lives in the heart and pulmonary arteries of an infected dog (a regular host), and cats (an abnormal host). Heartworm disease most commonly affects dogs, cats and ferrets, but heartworms can also live in other mammal species, including wolves, coyotes, foxes, and sea lions.

How does heartworm spread?

Dogs and cats acquire this infection through mosquito bites as mosquitoes readily pick up larval heartworms from infected dogs and carry them to new dogs. Adult female heartworms living in an infected dog, fox, coyote, or wolf produce microscopic baby worms called microfilaria that circulate in the bloodstream. When a mosquito bites and takes a blood meal from an infected animal, it picks up these baby worms, which develop and mature into “infective stage” larvae over a period of 10 to 14 days. Then, when the infected mosquito bites another dog, cat, or susceptible wild animal, the infective larvae are deposited onto the surface of the animal's skin and enter the new host through the mosquito’s bite wound. Once inside a new host, it takes approximately 6 months for the larvae to mature into adult heartworms. Once mature, heartworms can live for 5 to 7 years in dogs and up to 2 or 3 years in cats.

What happens when my dog has heartworm?

The adult heartworm is fairly large and it prefers to live not in the heart, but in the pulmonary arteries. It swims into a cozy tubular artery where it is massaged and nourished by the blood coursing past it. In the pulmonary arteries of an infected dog, the worm generates a strong inflammatory response and a tendency for blood to inappropriately clot. If there are a lot of worms, the heart must work extra hard to pump blood through the plugged-up arteries.  This affects the amount of blood that reaches other vital organs such as the lungs. Signs of heartworm disease may include a mild persistent cough, reluctance to exercise, fatigue after moderate activity, decreased appetite, and weight loss. As heartworm disease progresses, pets may develop heart failure and the appearance of a swollen belly due to excess fluid in the abdomen. 

Can my cat get heartworm disease?

Yes. It is difficult for fully grown heartworms to live inside of cats so they are often considered abnormal hosts. Signs of heartworm disease in cats can be very subtle or very dramatic. Symptoms may include coughing, asthma-like attacks, periodic vomiting, lack of appetite, or weight loss. Occasionally an affected cat may have difficulty walking, experience fainting or seizures, or suffer from fluid accumulation in the abdomen. Unfortunately, the first sign in some cases is sudden collapse of the cat, or sudden death. There is no approved treatment for heartworm infection in cats. Prevention is critical! 

Do we have heartworm in Humboldt County?

“I heard we don’t have heartworms on the coast, it’s much too cold for heartworms to survive in Eureka.”

While the risk of heartworm is reduced on the coast of Humboldt County, we still have heartworm in the area and it is highly recommended to be on prevention year round. Here in Humboldt we often travel with our dogs to warmer inland areas, especially as summer approaches. Don’t risk your dog’s health! Keep them protected year round with heartworm prevention.

How do I test my dog or cat for heartworm?

Start by calling our office to schedule an appointment.

We offer two types of in-house heartworm tests for dogs. The first test is for heartworm exclusively. The second test option is called a 4dx and it tests for Heartworm and three tick borne diseases (lyme, ehrlichia, anaplasma). Both of these tests take about 10 minutes to run in office.

We also have an in-house combo test for cats which screens for heartworm FIV and Feline Leukemia.

As part of National Heartworm Disease Awareness month we are offering 10% off all Heartworm Testing through the month of April.


Ask us about your preventative options!

Heartworm Prevention is easy! Prevention can range anywhere from $8-$30 a month depending on the size of your animal and the type of prevention you choose. Talk to your vet to see what type of prevention best fits your lifestyle. We offer oral and topical prevention options that can prevent heartworm, intestinal parasites, and in some cases fleas! All heartworm prevention should be given every 30 days all 12 months out of the year.

It is not recommended to only offer heartworm prevention in the warmer months.


To learn more about heartworm disease, visit the link below