Life Cycle. Eggs are laid in the pulmonary arteries and are trapped in capillaries where they hatch. The larvas emerge into alveoli and move up the trachea to the pharynx where they are swallowed and passed in the feces. Larvas enter snails or slugs and undergo 2 molts. Dogs become infected by ingesting infected snails, slugs or their hosts. The 3rd stage larvas migrate from the intestine into lymph nodes and to the pulmonary arteries. The prepatent period is 7 weeks and adults may live in the host for over 2 years..

Clinical Features. Obstruction of pulmonary arteries by adult worms and obstruction of arterioles and capillaries by larvas lead to perivascular fibrosis and endocarditis of the tricuspid valve. Sequels can be congestive cardiac failure and cardiac insufficiency. Signs may include anorexia, coughing and dyspnea.

Diagnosis. Demonstration of larvas in feces and saliva.

Treatment and Control. Levamisole, fenbendazole and mebendazole have been effective. Many other deparasitizing drugs against nematodes work well.

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