Strongyloides ratti is a common gastro-intestinal parasite of the rat. The adult parasites are female only, about 2mm long and live in the mucosa of the small intestine. These parasites produce eggs that pass out of the host in its faeces. In the environment infective larval stages develop either directly or after a facultative sexual free-living adult generation. Infective larvae infect hosts by skin penetration.
S. ratti is the laboratory analogue of the parasite of humans, S. stercoralis . S. stercoralis is a wide-spread parasite of humans, occurring principally in the tropics and sub-tropics: some 100-200 million people are infected worldwide. Infection of immunosuppressed individuals can result in disseminated strongyloidiasis, in which worms occur throughout the body. This can be fatal unless anti-Strongyloides therapy is given. Other species of Strongyloides parasitise a wide range of vertebrates.
Sex Determination: alternates gonochoristic with XX parthenogenetic
Haploid No. chromosomes: 3 (2 autosomes, XY)