Angiostrongylus vasorum

Angiostrongylus vasorum ( "French heartworm " ) is a parasite in canids, infects the pulmonary trunk, the pulmonary arteries and the right ventricle. Principal definitive host of the parasite are foxes, but also dogs, wolves, badgers, coyotes and red pandas are attacked. Cats can be infected experimentally, but natural infections are thought to play no role. Adult worms are very thin ( 170-360 microns ), 1.4 to 2 cm long and pink.

Occurrence

Originally the parasite, especially in France, Denmark and the UK was widespread. In Germany ( and other parts of Europe ), the infection rate has been rising for several years to clear. In South and North America, Australia and Africa, and the Asian part of Russia the pathogen is now proved. Are typical in the endemic areas relatively small regional herd (cluster ) with an increased incidence of the parasite.

A German study showed an infection rate of 7.4 % at 810 examined dogs with unexplained pulmonary symptoms. Overall the prevalence in recent years has increased from 0.1 to 0.5%.

Development cycle

The prepatent period varied between 35 and 60 days. Female worms lay eggs undifferentiated, which pass via the bloodstream to the pulmonary capillaries, where the larvae hatch 1 and migrate to the lower airways. The larvae are coughed up, abgeschluckt and excreted in the feces. The precipitation time ( patency ) is up to 5 years. In intermediate hosts (various species of snails ) they develop into infective larvae 3 Occasionally also serve frogs as paratenic hosts. The dog eats an intermediate or paratenic host, the larvae penetrate the intestinal wall 3 a and evolve in the lymph nodes of the abdominal cavity. However, the larval stage 3 can also actively emerge from the snails and in a moist environment to survive up to 15 days so that an infection on the incorporation of grass and dew is possible. After infection, the larvae reach about portal vein, liver and inferior vena cava into the right ventricle and the pulmonary arteries, where they molt to the adult worms.