Observations of size variation in trematodes infecting red-sided garter snakes\ud (Thamnophis sirtalis parietalis)

"Red-sided garter snakes, Thamnophis sirtalis parietalis, from Manitoba, Canada are known to be hosts to trematodes, Alaria sp., in their population. Alaria sp. have been located in the tail tissue of the snakes. The non-reproductive stage of these obligate endoparasites, known as a mesocercaria, is trophically acquired by garter snakes. The current study examined variation in the size of Alaria mesocercariae within male garter snakes and investigated potential relationships between mesocercaria size and infection intensity. The snakes used were part of a larger immunological study in which the snakes received injections of either lipopolysaccharide (LPS, a compound that promotes an immune response) or saline. The collection of tail tissue was carried out during necropsies of the snakes and preserved for isolation of the parasites. Total parasite counts were performed. During the counts, each sample was roughly categorized based on the relative size (small, medium, or large) of the parasites it contained. The data from the current study make a useful contribution to a larger project investigating the reproductive implications of trematode infections in garter snakes