''Hysterothylacium'' is a genus of parasitic roundworms in the family

Raphidascarididae Raphidascarididae is a family of roundworms (also known as nematodes) in the order Ascaridida. It encompasses nine genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well ...

. As of 2020 it consists of over 70 species and is considered one of the largest of the ascaridoid genera parasitising fish.

Ecology

Species in the genus complete their life cycle between predatory

teleost Teleostei (; Greek ''teleios'' "complete" + ''osteon'' "bone"), members of which are known as teleosts ), is, by far, the largest infraclass in the class Actinopterygii, the ray-finned fishes, containing 96% of all extant species of fish. Tel ...

fish as their final host and various species of invertebrates and teleost as their intermediate hosts. These parasites are not host specific in the larval stages and infect a broad range of fish species; thus they are widely distributed throughout the aquatic ecosystem and exhibit a global distribution. '' Hysterothylacium aduncum'' infection in fish has been associated with mechanical damage to the heart, eye and fish musculature which occurs as a result of parasite larval migration. Catastrophic loss of fish fry due to infection with an unknown species of ''Hysterothylacium'' has been reported. Human infection is not common but has been reported in Japan.

References

{{Taxonbar, from=Q5304574 Parasites Ascaridida Nematode genera