Strongyloides (from Greek strongylos, round, + eidos, resemblance), anguillula, or threadworm is a genus of small nematode parasites, belonging to the family Strongylidae, commonly found in the small intestine of mammals (particularly ruminants), that are characterized by an unusual lifecycle that involves one or several generations of free-living adult worms. Human infection, strongyloidiasis, is caused by Treatment for strongyloides infection is ivermectin or thiabendazole.