State Key Laboratory of Bioreactor Engineering, School of Resource and Environmental, East China University of Science and Technology, Shanghai, 200237, China.
Key Laboratory of Zoonosis of Ministry of Agriculture, College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China.
Parasit Vectors. 2018 Mar 12;11(1):170. doi: 10.1186/s13071-018-2768-x.
Cattle are commonly infected with the microsporidian parasite Enterocytozoon bieneusi. Sequence characterization of E. bieneusi in these animals at the ribosomal internal transcribed spacer (ITS) locus had identified I, J and BEB4 as the dominant genotypes. However, current studies on E. bieneusi in dairy cattle are mostly on infection rates and genotype distribution. This study aims to examine the intragenotypic diversity within dominant E. bieneusi genotypes in pre-weaned dairy calves in Shanghai, China.
Enterocytozoon bieneusi genotypes and subtypes were identified by PCR sequence analysis of ITS and multilocus sequence typing (MLST), based on material from farms. Chi-square test was used to examine differences in E. bieneusi infection rates between farms or age groups.
The overall infection rate of E. bieneusi was 26.5% (214/809), ranging from 12.6% (Farm 5) to 38.5% (Farm 4). Infection rates increased with age during early life, with the peak infection rate (43.0%; 43/100) occurring at six weeks. Four genotypes were present, including J (n = 145, 67.8%), BEB4 (n = 59, 27.6%), CHN4 (n = 4, 1.9%) and CHN15 (n = 1, 0.5%), with the former two belonging to Group 2 and the latter two belonging to Group 1. Differences were detected in the distribution of the dominant genotypes J and BEB4 among five study farms. Altogether, 10 multilocus genotypes (MLGs) were identified in the two dominant ITS genotypes, including MLG-J1 to MLG-J8 of genotype J and MLG-B1 to MLG-B2 of genotype BEB4. MLG-B1 and MLG-B2 were recovered in Farms 1, 2 and 5, whereas MLG-J1 to MLG-J5 and MLG-J6 to MLG-J8 were found in Farms 3 and 4, respectively.
There is extensive genetic heterogeneity within the dominant E. bieneusi genotypes J and BEB4 in dairy calves in Shanghai, China, and MLST should be used in molecular epidemiological studies of E. bieneusi in cattle.
牛通常会感染微孢子虫寄生虫肠上皮细胞朊病毒。对这些动物核糖体内部转录间隔区（ITS）基因座的肠上皮细胞朊病毒 E. bieneusi 进行序列特征分析，确定 I、J 和 BEB4 为主要基因型。然而，目前对奶牛中肠上皮细胞朊病毒 E. bieneusi 的研究主要集中在感染率和基因型分布上。本研究旨在检测上海地区未断奶奶牛中主要肠上皮细胞朊病毒 E. bieneusi 基因型内的种内多样性。
根据农场的材料，通过 PCR 序列分析 ITS 和多位点序列分型（MLST）来鉴定肠上皮细胞朊病毒 E. bieneusi 基因型和亚型。卡方检验用于检验农场或年龄组之间肠上皮细胞朊病毒 E. bieneusi 感染率的差异。
肠上皮细胞朊病毒 E. bieneusi 的总感染率为 26.5%（214/809），范围为 12.6%（农场 5）至 38.5%（农场 4）。在生命早期，随着年龄的增长，感染率逐渐增加，6 周时的感染率达到峰值（43.0%；43/100）。共存在 4 种基因型，包括 J（n=145，67.8%）、BEB4（n=59，27.6%）、CHN4（n=4，1.9%）和 CHN15（n=1，0.5%），前两种属于第 2 组，后两种属于第 1 组。在五个研究农场中，J 和 BEB4 两种主要基因型的分布存在差异。在这两种主要的 ITS 基因型中，共鉴定出 10 种多位点基因型（MLGs），包括基因型 J 的 MLG-J1 至 MLG-J8 和基因型 BEB4 的 MLG-B1 至 MLG-B2。MLG-B1 和 MLG-B2 存在于农场 1、2 和 5，而 MLG-J1 至 MLG-J5 和 MLG-J6 至 MLG-J8 存在于农场 3 和 4。
在中国上海的奶牛中，肠上皮细胞朊病毒 E. bieneusi 的主要基因型 J 和 BEB4 内存在广泛的遗传异质性，在牛的肠上皮细胞朊病毒 E. bieneusi 的分子流行病学研究中应使用 MLST。
