What type of parasite is heartworm?

Heartworm is classified as a nematode, specifically Dirofilaria immitis. This organism is a type of roundworm that primarily affects dogs but can also infect cats and other animals. Heartworms are transmitted through mosquito bites, with the larvae entering the host's bloodstream and ultimately maturing into adult worms that reside in the heart and pulmonary arteries. This classification as a nematode is crucial for understanding its biology and the appropriate treatment methods.

Protozoans are single-celled organisms, which heartworms are not, and they typically cause very different types of diseases. Cestodes, or tapeworms, are flatworms that have a distinct mode of reproduction and life cycle compared to nematodes. Ectoparasites are organisms like fleas and ticks that live on the outside of their hosts, which is unlike heartworms that live within the host's circulatory system. Recognizing the type of parasite is essential for diagnosis and treatment in veterinary medicine, particularly concerning heartworm prevention and management strategies.