Heartworms & Other Parasites

What Are Heartworms?

Heartworm disease is a parasitic infection that can affect any dog regardless of age, sex or habitat. Heartworm disease is found in virtually all parts of the United States and many parts of Canada. Heartworms are spread by mosquitoes. The disease tends to have a higher incidence in areas heavily populated by mosquitoes.

Heartworms live in the blood of a dog's heart and adjacent blood vessels. They can grow from 4-12 inches in length, reach maturation one year after infection and live for approximately 5-7 years. Adult heartworms produce offspring, known as microfilariae, which circulate in the animal's blood. When a female mosquito bites an infected animal, it sucks blood containing the microfilariae. When the mosquito bites another pet, the infected larvae are transmitted. In many cases the infected dog will not show symptoms in the early stages of the disease process.

Tick-Borne Diseases

Heartworms are the most serious common parasite for dogs because they stress the dog's heart by restricting blood flow and also damage other internal organs. The heart may enlarge and become weakened due to an increased workload, and congestive heart failure may occur. Left untreated, the disease can be fatal to dogs. Blood screening tests can verify the presence of heartworms. Radiographs and x-rays are used to detect the disease in its later stages. Prompt detection prevents needless suffering.