Multilocus phylogenetic analysis of Cryptosporidium andersoni (Apicomplexa) isolated from a bactrian camel (Camelus bactrianus) in China.

This is the first report of cryptosporidiosis in a bactrian camel (Camelus bactrianus) in China. Two Cryptosporidium isolates derived from the same bactrian camel (3-year-old) in November 2005 and April 2006 were characterized using sequence and phylogenetic analysis of the small-subunit rRNA (18S rRNA), 70-kDa heat shock protein (HSP70), actin and Cryptosporidium oocyst wall protein (COWP) genes. The sequences of the 18S rRNA and COWP were identical to all other Cryptosporidium andersoni isolates although minor differences were noticed between the isolates and the USA isolate at the actin locus (99.2% of similarity). The sequence of the HSP70 was identical to the Japanese C. andersoni isolate, with a minor difference from the Australian C. andersoni isolate (99.7% of similarity). Cross-transmission studies demonstrated that the C. andersoni isolates did not infect immunosuppressed or immunocompetent Kun-ming mice, severe combined immunodeficiency mice, and immunosuppressed or immunocompetent calves. Among the C. andersoni isolates reported so far, only isolates from Japan could infect SCID mice. Thus, the C. andersoni isolates from the bactrian camel were biologically similar to most bovine C. andersoni isolates characterized so far, but are different from bovine isolates from Japan.