Possible contamination of surface waters with Giardia spp. through muskrats

Muskrats were examined for Giardia infections. Collected faecal samples were processed by means of sucrose density gradient centrifugation, using a 1 M sucrose solution. Identification of cysts was done by phase contrast microscopy, by the immunofluorescence test, or by both methods. From July 1994 to September 1995, a total of 234 muskrats from two different geographical areas in western parts of Germany were examined for the presence of Giardia cysts. 176 animals (75.2%) were found to be Giardia-positive. This study corroborates the assumption that animals such as muskrats living close to surface water bodies could contaminate water bodies with parasites such as Giardia.