Prevalence and genotypic variation of cryptosporidium spp. in mesocarnivores, opossums, and dairy calves

This study examined the prevalence of Cryptosporidium species in mammalian wildlife, including raccoons (Procyon lotor), gray foxes (Urocyon cinereoargenteus), striped skunks (Mephitis mephitis), and opossums (Didelphis virginiana) in association with dairy calves (Bos taurus). Cryptosporidium species have recently been differentiated into a variety of genotypes and strains, but the ecological associations among them is vague. I genetically identified the species and genotypes of Cryptosporidium found in the feces of naturally infected wildlife and dairy calves using DNA sequence analysis of the 18S rRNA gene. Of the 148 fecal samples obtained, Cryptosporidium infections were present in 17.0% of raccoons (n = 53), 44.0% of opossums (n = 25), 14.3% of striped skunks (n = 14), 33.3% of gray foxes (n = 3), and 37.7% of dairy calves (n = 53) and included 8 different species and genotypes: C. parvum bovine genotype, C. baileyi, C. andersoni, C. bovis, opossum genotype I, opossum genotype II, a skunk genotype, and a vole genotype. Evaluation of the prevalence and association of strains with different hosts was used to help identify the direction of transmission as well as risks for wildlife, cattle, and people. This study supports sylvatic transmission of certain Cryptosporidium species and genotypes among wildlife and indicates that dairy calves are the predominant host of Cryptosporidium spp. that poses a human health concern.