<i>Cryptosporidium</i> spp. Infection and Genotype Identification in Pre-Weaned and Post-Weaned Calves in Yunnan Province, China

Background: <i>Cryptosporidium</i> is a globally distributed zoonotic protozoan parasite in humans and animals. Infection is widespread in dairy cattle, especially in calves, resulting in neonatal enteritis, production losses and high mortality. However, the occurrence of <i>Cryptosporidium</i> spp. in pre- and post-weaned calves in Yunnan Province remains unclear. Methods: We collected 498 fecal samples from Holstein calves on 10 different farms in four regions of Yunnan Province. Nested PCR and DNA sequencing were used to determine the infection, species and genotypes of <i>Cryptosporidium</i> spp. in these animals. Results: The overall occurrence of <i>Cryptosporidium</i> spp. in Holstein calves was 32.9% (164/498), and the prevalence in pre- and post-weaned calves was 33.5% (106/316) and 31.9% (58/182), respectively. Four <i>Cryptosporidium</i> species were identified in these animals, namely <i>C. bovis</i> (<i>n</i> = 119), <i>C. parvum</i> (<i>n</i> = 23), <i>C. ryanae</i> (<i>n</i> = 20) and <i>C. andersoni</i> (<i>n</i> = 2). Based on sequencing analysis of the 60 kDa glycoprotein gene of <i>C. bovis</i>, <i>C. parvum</i> and <i>C. ryanae</i>, six subtypes of <i>C. bovis</i> (XXVIe, XXVIb, XXVIf, XXVIa XXVIc and XXVId), two subtypes of <i>C. parvum</i> (IIdA19G1 and IIdA18G1) and four subtypes of <i>C. ryanae</i> (XXIf, XXId, XXIe and XXIg) were identified. Conclusions: These results provide essential information to understand the infection rate, species diversity and genetic structure of <i>Cryptosporidium</i> spp. populations in Holstein pre-weaned and post-weaned calves in Yunnan Province. Further, the presence of IIdA18G1 and IIdA19G1 in <i>C. parvum</i> implies significant animal and public health concerns, which requires greater attention and more preventive measures.