中国东北黑龙江省奶牛和肉牛中安氏隐孢子虫的多位点序列分型亚型及群体遗传结构
MLST subtypes and population genetic structure of Cryptosporidium andersoni from dairy cattle and beef cattle in northeastern China's Heilongjiang Province.
作者信息
Zhao Wei, Wang Rongjun, Zhang Weizhe, Liu Aiqin, Cao Jianping, Shen Yujuan, Yang Fengkun, Zhang Longxian
机构信息
Department of Parasitology, Harbin Medical University, Harbin, Heilongjiang, China.
College of Animal Science and Veterinary Medicine, Henan Agricultural University Zhengzhou, Henan, China.
出版信息
PLoS One. 2014 Jul 7;9(7):e102006. doi: 10.1371/journal.pone.0102006. eCollection 2014.
Cattle are the main reservoir host of C. andersoni, which shows a predominance in yearlings and adults of cattle. To understand the subtypes of C. andersoni and the population genetic structure in Heilongjiang Province, fecal specimens were collected from 420 dairy cattle and 405 beef cattle at the age of 12-14 months in eight cattle farms in five areas within this province and were screened for the presence of Cryptosporidium oocysts by microscopy after Sheather's sugar flotation technique. The average prevalence of Cryptosporidium spp. was 19.15% (158/825) and all the Cryptosporidium isolates were identified as C. andersoni by the SSU rRNA gene nested PCR-RFLP using SspI, VspI and MboII restriction enzymes. A total of 50 C. andersoni isolates were randomly selected and sequenced to confirm the RFLP results before they were subtyped by multilocus sequence typing (MLST) at the four microsatellite/minisatellite loci (MS1, MS2, MS3 and MS16). Four, one, two and one haplotypes were obtained at the four loci, respectively. The MLST subtype A4,A4,A4,A1 showed an absolute predominance and a wide distribution among the six MLST subtypes obtained in the investigated areas. Linkage disequilibrium analysis showed the presence of a clonal population genetic structure of C. andersoni in cattle, suggesting the absence of recombination among lineages. The finding of a clonal population genetic structure indicated that the prevalence of C. andersoni in cattle in Heilongjiang Province is not attributed to the introduction of cattle. Thus, prevention and control strategies should be focused on making stricter measures to avoid the occurrence of cross-transmission and re-infection between cattle individuals. These molecular data will also be helpful to explore the source attribution of infection/contamination of C. andersoni and to elucidate its transmission dynamics in Heilongjiang Province, even in China.
牛是安氏隐孢子虫的主要储存宿主，该寄生虫在一岁龄和成年牛中占主导地位。为了解黑龙江省安氏隐孢子虫的亚型及种群遗传结构，在该省五个地区的八个养牛场，采集了420头奶牛和405头12 - 14月龄肉牛的粪便样本，经Sheather糖浮选技术处理后，通过显微镜检查筛选隐孢子虫卵囊的存在情况。隐孢子虫属的平均感染率为19.15%（158/825），使用SspI、VspI和MboII限制性内切酶，通过SSU rRNA基因巢式PCR - RFLP将所有隐孢子虫分离株鉴定为安氏隐孢子虫。随机选择50株安氏隐孢子虫分离株进行测序以确认RFLP结果，然后在四个微卫星/小卫星位点（MS1、MS2、MS3和MS16）通过多位点序列分型（MLST）进行亚型分析。在这四个位点分别获得了四种、一种、两种和一种单倍型。MLST亚型A4、A4、A4、A1在所研究区域获得的六种MLST亚型中占绝对优势且分布广泛。连锁不平衡分析表明牛体内安氏隐孢子虫存在克隆种群遗传结构，这表明不同谱系之间不存在重组。克隆种群遗传结构的发现表明，黑龙江省牛群中安氏隐孢子虫的流行并非归因于牛的引入。因此，预防和控制策略应侧重于制定更严格的措施，以避免牛个体之间发生交叉传播和再感染。这些分子数据也将有助于探索安氏隐孢子虫感染/污染的来源归因，并阐明其在黑龙江省乃至中国的传播动态。
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