新疆阿克苏地区蜱和羊感染无浆体的分子流行病学调查

Molecular Epidemiological Investigation of Anaplasma Infection in Ticks and Sheep in Aksu Prefecture,Xinjiang Uygur Autonomous Region

[目的]了解新疆阿克苏地区蜱与羊感染无浆体的情况。[方法]共采集192只蜱和477份羊抗凝血样品;以线粒体16S rDNA和ITS-2为靶基因,采用PCR法对经过形态学鉴定的蜱虫进行分子生物学鉴定;利用特异性引物,分别采用普通PCR法及巢式PCR法检测绵羊无浆体(Ananlasma ovis,A.ovis)和嗜吞噬细胞无浆体(Ananlasma phagocytophilum,A.phagocytophilum)在蜱和羊抗凝血样品中的携带情况;采用统计学方法分析不同种类、性别蜱虫和不同区域、不同饲养模式下羊感染上述2种无浆体的情况。[结果]采集到的192只蜱虫包括雄蜱79只、雌蜱113只,共有2属3种,分别为扇头蜱属的图兰扇头蜱(Rhipicephalus turanicus,R.turanicus)以及璃眼蜱属的亚洲璃眼蜱(Hyalomma asiaticm,H.asiaticm)和小亚璃眼蜱(Hyalomma anatolicm,H.anatolicm),所占比例分别为52.60%、45.83%、1.56%。蜱样品中,感染2种无浆体的总体阳性率为7.29%,未检测到A.ovis和A.phagocytophilum混合感染;R.turanicus、H.asiaticm、H.anatolicm感染无浆体的阳性率分别为8.91%、5.68%、0,三者差异有统计学意义(χ^(2)=3.20,P<0.05);雄蜱和雌蜱感染无浆体的阳性率分别为6.33%、7.96%,二者差异无统计学意义(χ2=0.30,P>0.05)。羊抗凝血样品中,感染2种无浆体的总体阳性率为51.15%,与蜱样品的总体阳性率差异有统计学意义(χ^(2)=111.35,P<0.05);A.ovis与A.phagocytophilum混合感染率为16.56%;舍饲羊和散养羊感染无浆体阳性率分别为28.16%和83.00%,二者差异有统计学意义(χ^(2)=139.81,P<0.05);库车市和沙雅县羊无浆体阳性率最低,为5.00%,温宿县阳性率最高,为64.83%,二者差异有统计学意义(χ^(2)=27.72,P<0.05)。[结论]阿克苏地区蜱和羊普遍感染无浆体,应该加强对无浆体病的防治工作。

[Objective]The aim of this study was to understand the prevalence of Anaplasma infection in ticks and sheep in Aksu Prefecture of Xinjiang Uygur Autonomous Region.[Method]A total of 192 ticks and 477 sheep anticoagulant blood samples were collected.After morphological identification,the ticks were molecularly confirmed by using PCR assays targeting mitochondrial 16S rDNA and ITS-2 genes.The presence of Anaplasma ovis(A.ovis)and Ananlasma phagocytophilum(A.phagocytophilum)in the ticks and sheep anticoagulant blood samples were detected by using conventional PCR assay and nested PCR assay with specific primers,respectively.Statistical analysis were performed to assess the the differences in prevalence of A.ovis and A.phagocytophilum among ticks of different genders as well as sheep reared in various regions and feeding modes.[Result]The 192 ticks,including 79 male ticks and 113 female ticks,belonged to 2 genera and 3 species.The number of ticks identified as Rhipicephalus turanicus(R.turanicus),Hyalomma asiaticm(H.asiaticm)and Hyalomma anatolicum(H.anatolicum)accounted for 52.60%,45.83%and 1.56%of the total,respectively.In the tick samples,the overall positive rate of Anaplasma infection was 7.29%,while the mixed infection of A.ovis and A.phagocytophilum was not observed;the positive rates of Anaplasma infection for R.turanicus,H.asiaticm,and H.anatolicm were 8.91%,5.68%,and 0,respectively,with statistically significant differences(χ^(2)=3.20,P<0.05);the positive rates of Anaplasma infection for male and female ticks were 6.33%and 7.96%,respectively,with no statistically significant difference(χ^(2)=0.30,P>0.05).In the sheep anticoagulant blood samples,the overall positive rate of Anaplasma infection was 51.15%,which had statistically significant difference with that of the tick samples(χ^(2)=111.35,P<0.05);the mixed infection rate of A.ovis and A.phagocytophilum was 16.56%;the positive rates of Anaplasma infection in captive and free range sheep were 28.16%and 83.00%,respectively,with statistically significant difference(χ^(2)=139.81,P<0.05);Kuqa City and Xayar County had the lowest positive rate of Anaplasma infection at 5.00%,and Wensu County had the highest positive rate at 64.83%,with statistically significant difference(χ^(2)=27.72,P<0.05).[Conclusion]The prevalence of Anaplasma infection in ticks and sheep in Aksu Prefecture was common,and the prevention and control of anaplasmosis should be strengthened.