Heartworm disease may result in severe lung disease, heart failure, other organ damage, and may lead to death in pets.

Heartworm disease is a serious disease that results in severe lung disease, heart failure, other organ damage, and may lead to death in pets, mainly dogs, cats, and ferrets. It is caused by a parasitic worm called Dirofilaria immitis. The worms are spread through the bite of a mosquito. The dog is the definitive host, meaning that the worms mature into adults, mate, and produce offspring while living inside a dog. The mosquito is the intermediate host, meaning that the worms live inside a mosquito for a short transition period in order to become infective (able to cause heartworm disease).

Dogs and cats of any age or breed are susceptible to infection.