Abstract

Cysts of Giardia sp. were detected in faeces from the rectum of 20 of 74 phocid seals examined from the east coast of Canada in 1997 and 1998 using a monoclonal antibody technique. Infected seals included: 15 adult harp seals (Phoca groenlandica), four adult grey seals (Halichoerus grypus) and one juvenile harbour seal (Phoca vitulina). Cysts were not detected in 17 pups of less than one year old. The highest prevalence (50%) was in adult harp seals collected near the Magdalene Islands in the Gulf of St. Lawrence. The overall prevalence of Giardia sp. in grey and harbour seals from the Gulf and St. Lawrence estuary was 25%. Faeces from 11 beluga (Delphinapterus leucas) and one northern bottle-nosed whale (Hyperoodon ampullatus) stranded in the St. Lawrence estuary were negative. The significance of Giardia sp. in marine mammals, shown here for the first time on the east coast of Canada, is unknown.