Strongyloides

Threadworm
First stage larva (L1) of S. stercoralis
Scientific classification
Kingdom:	Animalia
Phylum:	Nematoda
Class:	Secernentea
Order:	Rhabditida
Family:	Strongyloididae
Genus:	Strongyloides
Species
Strongyloides stercoralis Strongyloides fuelleborni Strongyloides ratti Strongyloides ransomi Strongyloides papillosus

Strongyloides (from Greek strongylos, round, + eidos, resemblance), Anguillula, or threadworm is a genus of small nematode parasites, belonging to the family Strongyloididae, commonly found in the small intestine of mammals (particularly ruminants), that are characterized by an unusual life cycle that involves one or several generations of free-living adult worms.

Human infection, strongyloidiasis, is chiefly caused by Strongyloides stercoralis, widespread in all tropical regions, or by Strongyloides fuelleborni, a parasite of primates in African and Asian tropics and of humans in African tropics and New Guinea. Other species include Strongyloides papillosus found in cows, pigs, sheep, goats, rabbits, and rats, Strongyloides ransomi found in pigs and Strongyloides ratti, found in rats.