Background: Cryptosporidium is a protozoan parasite causing diarrhoea in humans and animals. Although Cryptosporidium has been found in domestic horses (farmed or kept at pasture), there has been only one published study of Cryptosporidium infections in Chinese racehorses, which was restricted to a very small geographical area.
Objectives: To investigate the presence of Cryptosporidium spp. in the faeces of racehorses in China and to perform molecular characterisation of the parasite.
Study design: Cross-sectional.
Methods: A total of 621 fresh faecal samples were collected for DNA extraction from racehorses at 17 equestrian clubs from 12 provinces of China from December 2016 to May 2018. All the DNA were analysed for the presence of Cryptosporidium species/genotypes and subtypes by PCR amplification of the small subunit ribosomal RNA and 60 kDa glycoprotein genes respectively.
Results: PCR analysis revealed that 11 samples (1.8%) were positive for Cryptosporidium spp. Among them seven samples were identified as C. parvum and four were C. hominis. The C. parvum isolates were identified as subtype IIdA14G1 (n = 4) and IIdA15G1 (n = 3), while all C. hominis isolates were identified as subtype IkA18G1 (n = 4).
Main limitations: A single faecal sample from each horse was used instead of multiple samples that could improve the detection rates of the parasite.
Conclusions: Although Cryptosporidium infection rate was relatively low in the investigated racehorses, the presence of zoonotic subtypes IIdA14G and 1IIdA15G1 of C. parvum and IkA18G1 of C. hominis, suggesting that these animals are a potential source of Cryptosporidium in humans.
背景: 隐孢子虫(Cryptosporidium)是一种可以引起人类和动物腹泻的寄生性原虫。已有研究表明家养(圈养或放牧)马可以感染隐孢子虫, 但是关于中国赛马隐孢子虫感染情况的报道只有一篇, 且局限于较小的地理区域. 研究目的: 本研究旨在调查中国赛马粪便中隐孢子虫的阳性率, 并对检测到的隐孢子虫进行分子特征鉴定. 试验设计: 本研究设计为横断面研究. 研究方法: 本研究于 2016 年 12 月至 2018 年5月从中国 12 个省的 17个赛马俱乐部共采集赛马新鲜粪便样本 621 份。所有粪便样本均提取基因组 DNA 并分别基于小亚基核糖体 RNA(SSU rRNA) 基因和 60 千道尔顿糖蛋白 (gp60) 基因隐孢子虫种/基因型检测和亚型鉴定. 结果: PCR结果表明, 共有 11 份 (1.8%) 样品呈隐孢子虫阳性, 其中, 7 份样品被鉴定为微小隐孢子虫 (C. parvum), 4份样品被鉴定为人隐孢子虫 (C. hominis). 微小隐孢子虫分离株被进一步鉴定为 IIdA14G1 (n = 4) 和 IIdA15G1(n = 1) 亚型, 人隐孢子虫均被鉴定为 IkA18G1(n = 4) 亚型. 主要局限性: 本研究每个动物仅采样一份, 如果多次采样可以提高隐孢子虫的检出率. 结论: 尽管本研究查明的赛马隐孢子虫感染率相对较低, 但是微小隐孢子虫 IIdA14G1, IIdA15G1 亚型以及人隐孢子虫 IkA18G1 亚型的出现表明赛马可能是人感染的隐孢子虫的潜在源头.
Keywords: China; Cryptosporidium; genetic; horse; racehorse; subtype.
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