Genetical survey of novel type of Cryptosporidium andersoni in cattle in Japan

Previously, we reported that an isolate of novel type of Cryptosporidium andersoni detected in cattle in Japan contained Type A (identical to C. andersoni reported previously) and Type B (having a thymine nucleotide insertion unlike the Type A) genotypes in the 18S rRNA gene. Here, we conducted an extensive investigation of Cryptosporidium infections in adult cattle in Japan from 2004 to 2007. Consequently, Cryptosporidium sp. were detected in 12 of the 205 cattle examined (5.9%), and partial sequences of the Cryptosporidium oocyst wall protein (COWP) gene in all isolates were identical to those of the previously reported data for C. andersoni whereas two signals were observed in the sequence of the partial 18S rRNA gene in all the isolates. In transmission studies using five of the isolates, they all infected SCID mice. Modified multiplex PCR using DNA of a single oocyst isolated from the infected SCID mice revealed that the partial sequences in the 18S rRNA gene of 40-80% of 10 isolates were identical to the Type A genotype of C. andersoni and those of other samples were identical to the Type B genotype. These results suggested that the C. andersoni novel type is widespread in cattle throughout Japan, and have multiple copies (Types A and B) in the 18S rRNA gene.