Extinction of a species of land snail due to infection with a microsporidian parasite

Abstract

Snails of the genus Partula are highly endangered, with many species occurring solely in captivity. Captive populations experience periodic crashes, some of which have resulted in extinction. Pathologic investigations of the last individuals of a species that had undergone such a crash (Partula turgida) showed infection with a protozoan parasite as the cause of death. The parasite was identified as a member of the microsporidian genus Steinhausia, other members of which are known to cause mortality in aquatic pulmonate snails. We believe this is the first definitive report of an infectious disease causing the extinction of a species.