Heartworm is a parasitic disease that can affect any dog regardless of age, sex or habitat. It is found in virtually all parts of the United States and many parts of Canada.

Heartworm is spread by mosquitoes and tends to have a higher incidence in areas heavily populated by mosquitoes.

Dogs are considered the most common host for heartworms, however, heartworms may also infect more than thirty species of animals (including coyotes, foxes, wolves, domestic cats, ferrets) and even humans, though transmission from animal to human (zoonotic infection) is extremely rare.