PCR amplification and sequence analyses of ITS-1 rDNA from Cryptosporidium andersoni in dairy cattle.

The internal transcribed spacer 1 (ITS-1) of the ribosomal DNA (rDNA) from GD, HN, and AH strains of Cryptosporidium andersoni was amplified and sequenced to assess whether the ITS-1 rDNA could be used as genetic markers of C. andersoni from different geographic origins in China and to differentiate C. andersoni from other Cryptosporidium species. The result showed that the ITS-1 sequences of GD, HN, and AH strains were basically identical, which were unequivocally different with the sequences of the Cryptosporidium muris and Cryptosporidium parvum registered in the GenBank; however, the ITS-1 sequence of the AH strain differed at three bases compared with that of the other two strains. Our study indicates that the ITS-1 sequences provide useful genetic markers for the identification and differentiation of C. andersoni species and also lay down the foundation for diagnostics of cryptosporidiosis.