Both canines and felines are susceptible to heartworms. Heartworms are contracted from infected mosquitos, who deposit heartworm larvae via saliva into the animal’s bloodstream.
The larvae develop inside the tissues of their new host until they begin their migration to the heart and lungs where they will eventually mature into adult worms up to 18 inches long.
Fertilized adult female heartworms release microfilariae into the blood stream. A mosquito that bites the heartworm infected host, ingests the microfilariae and becomes infective starting the cycle all over again.