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-naïve 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 μm × 2.94–4.41 μm (mean = 3.94 μm × 3.44 μm) 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.