Cryptosporidium

Xiao, Xiao, Qi, Rui, Han, Hui-Ju, Liu, Jian-Wei, Qin, Xiang-Rong, Fang, Li-Zhu, Zhou, Chuan-Min, Gong, Xiao-Qing, Lei, Si-Cong & Yu, Xue-Jie, 2019, Molecular identification and phylogenetic analysis of Cryptosporidium, Hepatozoon and Spirometra in snakes from central China, International Journal for Parasitology: Parasites and Wildlife 10, pp. 274-280 : 276

3.1. Genotyping and subtyping Cryptosporidium

Among 149 snakes, 15 were positive to Cryptosporidium with an infection prevalence of 10.1% ( Table 2). BLAST analysis indicated that the sequences from the snakes belonged to three Cryptosporidium species. Ten sequences were 99.88–100% identical to each other and were identified as C. baileyi (6.7%, 10/149), three were 100% identical to C. parvum (2%, 3/149) and two were 100% identical to C. serpentis (1.3%, 2/149). Phylogenetic analysis using the four representative sequences also showed Cryptosporidium identifies in the present study clustered with C. baileyi , C. parvum and C. serpentis respectively ( Fig. 1 ). The three C. parvum sequences had 100% homology to previous isolates derived from dairy cattle (MF671870) in China. Of the ten C. baileyi sequences, seven were 99.88% homologous to previous isolates from quails (DQ89816) in China, and three were 100% homologous to previous isolates from chickens (JX548296) in Zhejiang Province and ducks (AY954882) in Henan Province, China. The two C. serpentis sequences were 100% homologous to previous isolates derived from the oriental rat snake Ptyas mucosus (KJ651433). The C. parvum samples were further subtyped with gp60 gene sequence. Two positive samples were 100% homologous with previous sequences of subtype IIdA15G1 from sheep (MH794167) in Xinjiang, China.

Figures

Fig. 1. Maximum likelihood phylogenetic tree based on the SSU gene of Cryptosporidium. The phylogenetic tree SSU gene (834bp) was constructed by using the Kimura 2-parameter model with MEGA 7.0 and the bootstrap values were calculated with 1000 replicates. Representative sequences of Cryptosporidium detected in snakes in this study are in bold print and marked by circles. Scale bar indicates nucleotide substitutions per site.