Ziekteverwekker
The French heartworm (Angiostrongylus vasorum) is a parasitic roundworm that can cause health problems in domestic and wild canids. Because this roundworm lives in the blood vessels of the lungs and the larvae migrate through the lungs, this worm is sometimes also called a lungworm.
French heartworm cycle
The French heartworm has a life cycle in which canids are the definitive hosts and snails (Gastropoda), both slugs and snails, are the intermediate hosts.
In canids, infectious larvae originating from the snail develop into adult male and female worms in the right ventricle and the blood vessels of the lungs and reproduce. The adult worms then excrete eggs that become lodged in the capillaries of the lungs. Larvae crawl out of these eggs and subsequently begin a migration through the lungs, are coughed up, and swallowed. These larvae are then excreted with the feces. Before these larvae can infect other canids, they must first develop within snails (intermediate hosts) into infectious (contagious) larvae for the canid. After a canid ingests the larvae originating from the snail, the cycle is complete.
The worm owes its name to the fact that it was first described by Baillet in France in 1866. The scientific name indicates that the adult worm lives in the blood vessels.
Since 2007, it has been known that this infection also occurs among domestic dogs in the Netherlands.
Gevoelige diersoorten
Canids, such as foxes, wolves, and dogs, can become infected with the French heartworm. However, infections have also been described in red pandas (in a zoo) and in an ermine (1).
Symptomen dieren
The symptoms are diverse. Clinical manifestations may include: difficulty breathing, coughing, heart failure, damage to the nervous system, blood clotting disorders, and gastrointestinal complaints. The clinical picture upon autopsy may include pneumonia, anemia, and blocked blood vessels, among others.
Besmetting dieren
Animals become infected by eating (parts of) an infected snail, whether intentionally or unintentionally, when eating carrion or chewing on sticks or grass. Frogs may possibly function as accidental (paratenic) intermediate hosts. It is unknown whether paratenic hosts play a role in infecting canids under natural conditions. Canids may also become infected by eating food contaminated with snail slime.
Sources
1 Morgan E.R. & S. Shaw (2010). Angiostrongylus vasorum infection in dogs: continuing spread and developments in diagnosis and treatment. Journal of Small Animal Practice 51, 616-621.
2 Gorris, F. (2015). Pathologie van Angiostrongylus vasorum bij de hond. Universiteit Gent, faculteit diergeneeskunde.
3 Doorn D.C.K. van, A.H. van de Sande, E.R. Nijsse, M. Eysker & H.W. Ploeger (2009). Autochthonous Angiostrongylus vasorum infection in dogs in The Netherlands. Veterinary Parasitology, Volume 162, Issues 1–2,2009,Pages 163-166.