PetMed Animal Health Center

2400 Gateway Dive
Dubuque, IA 52003



What Is It: Heartworm Disease is a very serious and often fatal disease in pets. It is caused by foot-long worms that grow and live in the heart, lungs, and blood vessels of the pet. 

Transmission: Heartworm disease is transmitted by mosquitoes. When a mosquito bites an infected animal and feeds on the blood, it picks up microscopic worms called microfilaria that are produced by the female heartworms. For about 10-14 days, the microfilaria develop into the larvae, known as the "infective stage". Once this stage is reached, they are able to infect the new host or pet once the mosquito bites into it. When the mosquito bites into another dog or cat, the larvae enter through the bite wound and infect the new host. 

Health Concerns: There are several great health concerns with this disease as it can be fatal. Heartworms can cause severe lung disease, heart failure, and damage to other organs in the body. 

Who Is At Risk:

Dogs- Dogs are a very natural host for heartworms because they are able to mature into adults, mate, and reproduce. When left untreated, the number of heartworms in a dog can increase to several hundreds of worms in their body. This disease causes the quality of life of the dog to decrease dramatically, even after the worms are gone.

Cats- Heartworm disease in cats is quite different than dogs. Cats are generally not a host for heartworms because most worms can't mature into adults. That being said, if a worm happens to make it to the adult stage, it is usually one to three that live. 


Monthly heartworm prevention and yearly testing is the best way to ensure that your pet does not contract this disease. We supply Tri-Heart Plus as the monthly preventative product. Prevention can be started in puppies as young as 6 weeks of age as well as pregnant female dogs. It is best the continue the prevention year round because missing one dose or stopping the prevention at all puts your dog at risk. Yearly testing is highly recommended because just like people, animals can become resistant to medication.