Cryptosporidium xiaoi n. sp. (Apicomplexa: Cryptosporidiidae) in sheep (Ovis aries).

A new species, Cryptosporidium xiaoi, is described from sheep. Oocysts of C. xiaoi, previously identified as the Cryptosporidium bovis-like genotype or as C. bovis from sheep in Spain, Tunisia, United Kingdom, and the United States are recorded as such in GenBank (EU408314-EU408317, EU327318-EU327320, EF362478, EF514234, DQ991389, and EF158461). Oocysts obtained from naturally infected sheep were infectious for a lamb and oocysts from that lamb were infectious for three other lambs. The prepatent period for C. xiaoi in these four Cryptosporidium-naive lambs was 7-8 days and the patent period was 13-15 days. Oocysts are similar to those of C. bovis but slightly smaller, measuring 2.94-4.41 microm x 2.94-4.41 microm (mean=3.94 microm x 3.44 microm) with a length/width shape index of 1.15 (n=25). Oocysts of C. xioai were not infectious for BALB/c mice, Bos taurus calves, or Capra aegagrus hircus kids. Fragments of the SSU-rDNA, HSP-70, and actin genes were amplified by PCR, purified, and PCR products were sequenced. The new species was distinct from all other Cryptosporidium species as demonstrated by multi-locus analysis of the 3 unlinked loci. Based on morphological, molecular and biological data, this geographically widespread parasite found in Ovis aries is recognized as a new species and is named C. xiaoi.