Host-AdaptedCryptosporidiumspp. in Canada Geese (Branta canadensis)

Abstract

The prevalence and distribution ofCryptosporidiumspp. in the fecal droppings of the free-living waterfowl Canada geese were examined at 13 sites in Ohio and Illinois. On the basis of the analysis of the small-subunit rRNA gene by PCR, followed by restriction fragment length polymorphism analysis and DNA sequencing, 49 (23.4%) of 209 fecal specimens collected from 10 sites (76.9%) were positive forCryptosporidiumspp. The following fiveCryptosporidiumspecies and genotypes were identified:Cryptosporidiumgoose genotype I (in 36 specimens),Cryptosporidiumgoose genotype II (in 9 specimens),Cryptosporidiumduck genotype (in 1 specimen),Cryptosporidium parvum(in 4 specimens), andC. hominis(in 2 specimens).Cryptosporidiumgoose genotype I was the most prevalent parasite and was found at all fiveCryptosporidium-positive sites in Ohio and at four of five positive sites in Illinois, followed byCryptosporidiumgoose genotype II, which was found at two of five positive sites in Ohio and at four of five positive sites in Illinois.Cryptosporidiumgoose genotype II was detected for the first time, and it is phylogenetically related to goose genotype I and the duck genotype. All three genotypes have not so far been reported in humans, and their pathogenicity in geese has not been determined. Only 10.2% of theCryptosporidium-positive specimens hadC. parvumandC. hominis. The results of this study indicate that Canada geese might only serve as accidental carriers of cryptosporidia infectious to humans and probably play a minor role in the animal-to-human transmission cycle of the pathogen.