山东省媒介蜱类种类鉴定及羊泰勒虫病流行病学调查

Identification of tick species and epidemiological survey of ovine theileria parasite infection in Shandong province

为了阐明山东省蜱类种类及羊泰勒虫病流行概况,于2012年3月-2013年11月采用形态学鉴定法鉴定收集的14 878只蜱类标本;采用梨形虫、泰勒科通用引物及种属特异性引物对617份羊血液样品进行PCR检测,并对阳性样品18SrRNA基因进行遗传进化分析;分析不同月份蜱类活动频率及羊泰勒虫感染率。结果显示山东省长角血蜱(Haemaphysalis longicornis)和草原革蜱(Dermacentor nuttalli)所占比例分别为75.3%和24.7%,统计学分析显示长角血蜱显著多于草原革蜱(P<0.05),为山东省优势蜱种。PCR检测结果显示山东省羊泰勒虫感染率为24.8%;其中吕氏泰勒虫感染率为12.0%、尤氏泰勒虫感染率为11.8%,混和感染率为5.3%,没有检测到绵阳泰勒虫感染,统计学分析显示吕氏泰勒虫和尤氏泰勒虫在羊群的感染率无统计学差异(P>0.05),吕氏泰勒虫与尤氏泰勒虫单虫种感染率显著高于混合感染率(P<0.05)。遗传进化分析显示山东省吕氏泰勒虫和尤氏泰勒虫与北京分离株分布于同一分支,而区别于西北地区和南方地区分离株,呈现区域聚集性;不同月份蜱类活动频率与羊泰勒虫感染率呈现季节相关性。上述结果表明山东省优势媒介蜱种为长角血蜱,羊泰勒虫感染虫种为吕氏泰勒虫和尤氏泰勒虫,感染率较高,且与媒介蜱类存在相关性,为山东省羊泰勒虫病防控提供科学实验依据。

To investigate the species of ticks and infection rate of theileria parasites in ovine from March 2012 to September 2013 in Shandong province.Species of 14 878 ticks were identified by morphological methods,617 blood samples were detected by PCR with universal primers of piroplasms and Theileria parasites as well as specific primers of Theileria luwenshuni,Theileria uilenbergi and Theileria ovis,and phylogenetic analysis were conducted based on 18 SrRNA of positive samples;dynamic amount of ticks and infection rate of Theileria parasites in different months in Shandong province were also analyzed.The results of tick species identification showed that Haemaphysalis longicornis and Dermacentor nuttalli were identified in the presented study,and accounted for 75.3% and 24.7%,respectively,Haemaphysalis longicornis predominated in Shandong province;PCR results showed infection rates of Theileria parasites were 24.8%,and infection rates of Theileria luwenshuni and Theileria uilenbergi were 12.0% and 11.8%,respectively,coinfection of Theileria luwenshuni and Theileria uilenbergi was 5.3%,no Theileria ovis was detected in the present study.No significant differences were observed between Theileria luwenshuni and Theileria uilenbergi(P>0.05),and single infection rate of Theileria luwenshuni or Theileria uilenbergi were also higher than co-infection(P<0.05).Phylogenetic analysis indicated Theileria luwenshuni and Theileria uilenbergi in the present study were in the same cluster with the Beijing strains,and separated from northwest strains or south strains,and the strains in the same cluster were distributed as the same area.In addition,the correlativity was observed between dynamic amount of ticks and infection rate of Theileria parasites in different months in Shandong province.These results indicated that Haemaphysalis longicorni spredominated in Shandong province,infection rates of Theileria luwenshuni and Theileria uilenbergi were high,and provided scientific data for prevention and control of ovine theileriosis in Shandong province.