Angiostrongylus vasorum, also known as French heartworm, is a species of parasitic nematode in the family Metastrongylidae.

The life cycle begins when L3 larvae are ingested by a definitive host, primarily the fox or dog.

The L5 larvae migrate through the portal circulation and through the liver and the adults end up at the pulmonary artery or right side of the heart.

The L1 larvae infect intermediate hosts (primarily slugs and snails) by penetrating the foot of the mollusc and develop to L3 within.

Chronic, coughing, exercise intolerance, dyspnea and tachypnea in young dogs is due to blood vessels being blocked by adults, eggs and larvae.

Blood tests, showing eosinophillia, poor clotting ability and speed as well as hypochromic anemia all point towards a diagnosis.

Some cases may also have hypercalcemia the cause of this unknown but may relate to granulomatous inflammation and macrophage production of alpha 1 hydroxylase.

Fecal examination using the Baerman technique are unreliable, as egg output is irregular and the pre-patent period of the parasite is relatively long.

[5] Natural definitive hosts are domestic dogs[4] and various other carnivores include:[6] Angiostrongylus vasorum lives in the right ventricle of the heart and the pulmonary artery.

[citation needed] Other known areas include Larvae of the first stage were found in Australia,[4] Argentina and Greece.

In endemic areas, monthly application will prevent angiostrongylosis and patent infection with Angiostrongylus vasorum.