Category Archives: Dog Heartworms

Heartworm Disease

Each year thousands of dogs become disabled or die from lung, heart or circulatory problems caused by the heartworm disease.

Heartworm disease in dogs and related canines is caused by a filarial nematode (thread-like round worm), Dirofilaria immitis. It is a major problem that promises to become more serious with time. The adult inhabits the right ventricle and pulmonary arteries, and because of its location in the heart, it is commonly called “the dog heartworm.” The parasite can only be transmitted from one dog to the other by some vector mosquito species.

Culex AdultDistribution

Heartworm is distributed worldwide in most tropical and subtropical regions, with increasing frequency in temperate climates. Until the late sixties, the disease was restricted to southern and eastern coastal regions of the United States. Now, however, cases have been reported in almost every state and in several provinces of Canada as shown here. Continue reading