Occurrence and molecular characterization of Cryptosporidium spp. in yaks (Bos grunniens) in China.

Compared with dairy and beef cattle, few data are available on the occurrence and distribution of Cryptosporidium species in yaks, which live in a very different habitat. In this study, 327 fecal specimens were collected from yaks in 4 counties in Qinghai Province of China and screened for Cryptosporidium by nested PCR analysis of the 18S rRNA gene. A total of 98 (30.0%) specimens were positive for Cryptosporidium. The occurrence of Cryptosporidium varied significantly among age groups; infection rates were 49.3% in weaned calves, 31.7% in yearlings, and 17.4% in adults. PCR products of all Cryptosporidium-positive specimens were successfully sequenced, with 56 specimens (57.1%) having C. bovis, 33 (33.7%) having C. ryanae, 2 (2.0%) having C. andersoni, 1 (1.0%) having C. ubiquitum, 1 (1.0%) having C. xiaoi, 2 (2.0%) having a novel genotype, and 3 (3.1%) having mixed infections of C. bovis and C. ryanae. There were some age-related differences in the distribution of Cryptosporidium species in post-weaned yaks examined. To our knowledge, this is the first report of C. andersoni, C. ubiquitum, C. xiaoi and a novel Cryptosporidium genotype in yaks. Published by Elsevier B.V.