河北省牛梨形虫流行病学调查及遗传进化分析

Epidemiological investigation and genetic evolution analysis of Bovine piroplasma in Hebei Province

为了解我国河北省牛梨形虫的种类、感染率、遗传进化及季节流行性情况,本研究共收集河北省7个地级市的牛血液样品564份,以提取的牛全血液基因组DNA为模板,采用套式PCR对牛梨形虫18S r RNA基因进行扩增检测,并鉴定虫种,选取10份不同地区牛犁形虫阳性样品测序,并构建其18S r RNA基因系统进化树分析其遗传进化特征。结果显示,我国河北省牛梨形虫总感染率为18.6%(105/564),其中张家口地区牛梨形虫感染率最高,为83.3%(20/24),极显著高于河北省其他地区(P<0.01),唐山、沧州、石家庄及承德的牛梨形虫感染率分别为27.4%(32/117)、22.1%(17/77)、25.0%(20/80)和19.0%(16/84),秦皇岛和衡水地区牛梨形虫感染率为0。感染梨形虫的虫种主要为双芽巴贝斯虫、牛巴贝斯虫和瑟氏泰勒虫,感染率最高的为双芽巴贝斯虫(12.2%,69/564)。18S r RNA基因的进化树分析结果显示,10份牛梨形虫18S r RNA基因均呈地区性聚集;统计学分析结果显示,8月份河北省牛梨形虫感染率最高(29.7%),显著高于其他月份(P<0.05),4月~8月间牛梨形虫感染率呈逐渐上升的趋势,8月份达到顶峰后感染率逐渐下降。本研究首次对河北省牛梨形虫进行了流行病学调查,并分析了其遗传进化特征,结果表明河北省存在牛梨形虫的感染,尤其是张家口地区,该地区应在夏季应加强对牛梨形虫的重点防控。本研究为河北省牛梨形虫的防制提供了科学依据。

In order to understand the species,infection rate,genetic evolution,and seasonal prevalence of Bovine piroplasma in Hebei Province,China,a total of 564 cattle blood samples from seven prefecture-level cities in Hebei Province were collected.Using whole blood genomic DNA as the template,the 18S rRNA gene sequence was amplified by nested PCR.The species were identified,and 10 positive samples from different regions were sequenced and a phylogenetic tree was constructed based on 18S rRNA gene to analyze their genetic characteristics.The results showed that the total infection rate of Bovine piroplasma in Hebei Province was 18.6%(105/564),with Zhangjiakou region having the highest infection rate of 83.3%(20/24),which was significantly higher than other regions in Hebei Province(P<0.01).The infection rates of Bovine piroplasma in Tangshan,Cangzhou,Shijiazhuang,and Chengde were 27.4%(32/117),22.1%(17/77),25.0%(20/80),and 19.0%(16/84),respectively.The infection rates of Bovine piroplasma in Qinhuangdao and Hengshui regions were 0.The main species of Bovine piroplasma infection were Babesia bigemina,Babesia bovis,and Theileria sergenti,with the highest infection rate being Babesia biflora at 12.2%(69/564).The genetic evolution tree showed that the 18S rRNA gene of 10 Bovine piroplasma all exhibited regional aggregation.Statistical analysis showed that the infection rate of Bovine piroplasma in Hebei Province was the highest in August(29.7%),which was significantly higher than other months(P<0.05);the infection rate of Bovine piroplasma showed a gradual upward trend from April to August,and gradually decreased after reaching its peak in August.The above results indicated that Bovine piroplasma infection was exsiting in Hebei Province,especially in the Zhangjiakou area,where key prevention and control measures for Bovine piroplasma should be strengthened during summer.