Multilocus genotype and subtype analysis of Cryptosporidium andersoni derived from a Bactrian camel (Camelus bactrianus) in China

Fecal specimens from two Bactrian camels were collected in the Ya'an city zoo of China and were examined for Cryptosporidium by centrifugal flotation. One specimen was found to be parasitized by Cryptosporidium via microscopy, and the oocysts were measured to have an average size of 7.03 x 5.50 mu m (n > 50). The isolate was genotyped by polymerase chain reaction (PCR) amplification and DNA sequence analysis of the partial 18S rRNA, COWP, and A135 genes, and was confirmed to be Cryptosporidium andersoni with minor nucleotide differences. Multilocus sequence typing (MLST) analysis indicated that the subtype of the camel-derived C. andersoni isolate was A4, A4, A4, and A1 at the four minisatellite loci (MS1, MS2, MS3, and MS16, respectively). Therefore, this isolate belongs to the most common MLST subtype reported in cattle in China and is distinct from two other known camel C. andersoni MLST subtypes (A6, A4, A2, A1 and A6, A5, A2, A1). Animal transmission experiments demonstrated that the C. andersoni isolate was not infectious to immunosuppressed or immunocompetent Kun-ming mice, Sprague-Dawley rats, and hamsters but was biologically similar to most bovine C. andersoni isolates characterized so far. Therefore, transmission of this camel-derived C. andersoni isolate is very likely to occur between camels and bovine.