Cryptosporidium spp. in Mink, Foxes, and Raccoon Dogs in Five Provinces of Northern China.

Cryptosporidium spp. is a common intestinal pathogen that causes diarrhea in both humans and animals. Northern China has a large-scale fur animal farming industry. Although there have been related studies, systematic data remain lacking. In this study, a total of 871 fecal samples were collected from fur animals in Shandong, Hebei, Liaoning, Jilin, and Heilongjiang provinces. Using nested polymerase chain reaction, 75 Cryptosporidium-positive samples were detected, and the overall infection rate was 8.61%. The infection rates ranged from 4.23% to 16.81% across different provinces, with the highest rate was observed in Shandong (16.81%, 19/113), followed by Jilin (15.07%, 11/73). Additionally, foxes (15.06%, 53/352) showed a higher infection rate compared with mink (4.55%, 13/286) and raccoon dogs (3.86%, 9/233), suggesting that foxes may be more susceptible. Four species/genotypes were identified: Cryptosporidium canis (n = 66), Cryptosporidium meleagridis (n = 1), Cryptosporidium parvum (n = 1), and mink genotype (n = 7). Among these, C. parvum and C. meleagridis were found in raccoon dogs and foxes, respectively, while the mink genotype was detected only in mink. C. canis was present in all three animal species and was the dominant species in foxes. These findings indicate that farmed fur animals may serve as potential reservoirs for Cryptosporidium transmission to humans. This study provides essential epidemiological data on Cryptosporidium infections in fur animals, contributing to a better understanding of its distribution and potential zoonotic risk.