Subtyping Cryptosporidium xiaoi, a Common Pathogen in Sheep and Goats.

Yingying Fan,Yaqiong Guo,Xin Yang,Lihua Xiao,Sheng Guo,Xitong Huang,Na Li,Fang Yang,Yaoyu Feng

doi:10.3390/pathogens10070800

Abstract

Cryptosporidiosis is a significant cause of diarrhea in sheep and goats. Among the over 40 established species of Cryptosporidium, Cryptosporidium xiaoi is one of the dominant species infecting ovine and caprine animals. The lack of subtyping tools makes it impossible to examine the transmission of this pathogen. In the present study, we identified and characterized the 60-kDa glycoprotein (gp60) gene by sequencing the genome of C. xiaoi. The GP60 protein of C. xiaoi had a signal peptide, a furin cleavage site of RSRR, a glycosylphosphatidylinositol anchor, and over 100 O-glycosylation sites. Based on the gp60 sequence, a subtyping tool was developed and used in characterizing C. xiaoi in 355 positive samples from sheep and goats in China. A high sequence heterogeneity was observed in the gp60 gene, with 94 sequence types in 12 subtype families, namely XXIIIa to XXIIIl. Co-infections with multiple subtypes were common in these animals, suggesting that genetic recombination might be responsible for the high diversity within C. xiaoi. This was supported by the mosaic sequence patterns among the subtype families. In addition, a potential host adaptation was identified within this species, reflected by the exclusive occurrence of XXIIIa, XXIIIc, XXIIIg, and XXIIIj in goats. This subtyping tool should be useful in studies of the genetic diversity and transmission dynamics of C. xiaoi.

Highlights

C. parvum and C. ubiquitum are zoonotic species that infect a wide range of hosts, while C. xiaoi appears to be adapted to ovine and caprine animals [3]
Similar to C. ubiquitum, C. canis, C. felis, and C. ryanae, the trinucleotide repeats of TCA/TCG/TCT encoding a polyserine tract at the 50 end of the gp60 gene and widely used to differentiate subtypes within subtype families, were absent in the gp60 sequence of C. xiaoi [12,13,17,24]
A polyserine tract encoded by AGC/AGT repeats was observed in the gp60 gene of the subtype family XXIIIl, and subtypes within XXIIIl differed mostly in the number of AGC/AGT repeats

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Cryptosporidium spp. are important diarrheal pathogens in humans and various animals [1]. 45 Cryptosporidium species and over 100 genotypes have been recognized [2]. C. parvum, C. ubiquitum, and C. xiaoi are common species in sheep and goats. C. parvum and C. ubiquitum are zoonotic species that infect a wide range of hosts, while C. xiaoi appears to be adapted to ovine and caprine animals [3]. C. xiaoi, previously known as the C. bovis-like genotype, is the most common species in sheep and goats in most areas except Europe [4,5,6,7,8]

Methods

Results

Discussion

Conclusion