ARS | Publication request: Giardia duodenalis and Cryptosporidium spp. in the intestinal contents of ringed seals (Phoca hispida) and bearded seals (Erignathus barbatus) in Nunavik, Quebec, Canada

Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 18, 2008
Publication Date: October 1, 2008
Citation: Dixon, B.R., Parrington, L.J., Parenteau, M., Leclair, D., Santin, M., Fayer, R. 2008. Giardia duodenalis and Cryptosporidium spp. in the intestinal contents of ringed seals (Phoca hispida) and bearded seals (Erignathus barbatus) in Nunavik, Quebec, Canada. Journal of Parasitology. 94(5):1161-1163.

Interpretive Summary: In addition to human infections, Giardia duodenalis and Cryptosporidium spp. have been found to infect livestock, companion animals and wildlife. These pathogens have been found to contaminate surface waters from land to sea. In the present study of intestinal contents of ringed and bearded seals harvested for food in the Nunavik region of northern Quebec, Canada Giardia duodenalis and Cryptosporidium spp. were found. Samples were analysed by cytometry, microscopy, and molecular methods. Giardia duodenalis was present in the intestinal contents of 80 percent of the ringed seals and 75 percent of the bearded seals tested, while Cryptosporidium spp. was present in 9 percent of the ringed seals and none of the bearded seals. Prevalence of both parasites was highest in animals less than one year of age. Giardia isolates from ringed seals were identified as G. duodenalis Assemblage B, which is commonly identified in human infections. The Cryptosporidium isolates from ringed seals were identified as C. muris, which has been reported in humans, and as two novel seal genotypes. The high prevalence of zoonotic G. duodenalis in both ringed and bearded seals, and the presence of C. muris in ringed seals, highlights the potential for zoonotic transmission to people that consume dried seal intestines and uncooked meat, and may contribute to the high prevalence of giardiasis found in Inuits in northern Canada.

Technical Abstract: The prevalence in intestinal contents of ringed and bearded seals harvested for food in the Nunavik region of northern Quebec, Canada was determned for Giardia and Cryptosporidium genotypes and species. Specimens were analysed by dual color flow cytometry, immunofluorescence microscopy, and polymerase chain reaction. Flow cytometric results demonstrated that G. duodenalis in intestinal contents of 80% of ringed seals and 75% of bearded seals tested, whereas Cryptosporidium spp. was present in 9% of ringed seals and no bearded seals. Prevalence of both parasites was highest in animals less than one year of age. Giardia isolates from ringed seals were identified as G. duodenalis Assemblage B, common in human infections. Cryptosporidium isolates from ringed seals were identified as C. muris, reported in humans, and as two novel seal genotypes. The high prevalence of zoonotic G. duodenalis in both ringed and bearded seals, and the presence of C. muris in ringed seals, highlights the potential for zoonotic transmission to the Inuit people that consume dried seal intestines and uncooked meat, and may contribute to the high prevalence of giardiasis found in Inuits.