New subtype of Cryptosporidium cuniculus isolated from rabbits by sequencing the Gp60 gene.

Given the paucity of literature available on rabbits infected with Cryptosporidium in Sichuan Province (China), 290 fecal samples were collected from rabbits in the animal house of Sichuan Agricultural University, China and examined for Cryptosporidium oocysts using the Sheather's sucrose flotation technique and a modified acid-fast staining method. Three samples tested positive (prevalence = 1.03%). The positive isolates were genotyped by sequence analysis of the 18S rRNA, HSP70, COWP, and Cp135 genes and characterized by PCR-restriction fragment length polymorphism (RFLP) analysis of the 18S rRNA gene. Phylogenetic analysis was established using the neighbor-joining (NJ) method. All the isolates were identified as Cryptosporidium cuniculus. Further subtyping of the positive isolates was performed by DNA sequencing of the 60-kDa glycoprotein (gp60) gene. Only 1 subtype family was detected, Va, which was proposed to be a new subtype, VaA31. This study is the first report about the prevalence, genetic identification, and Cp135 gene of C. cuniculus in rabbits in Sichuan Province, China. The obtained results indicate that the C. cuniculus subtype in rabbits in Sichuan Province is unique.