云南省小型兽类感染无形体的分子流行病学调查

目的 了解云南省小型兽类感染无形体的种类及其分布,以掌握该地区小型兽类携带无形体对人、畜健康的危害,为无形体病的防控提供科学依据。方法 在云南省22个县(市)的130个采样点,捕获分属4目9科26属52种的小型兽类2 251只,取其脾脏组织提取DNA后,运用无形体通用引物,巢式PCR检测无形体16S rRNA 660 bp部分片段。阳性产物测序后,通过序列比对及系统进化分析确定感染无形体种类,结合样本信息分析流行病学意义。结果 共检出阳性样本27份, 产物序列经比对为23份A.phagocytophilum,4份未分类无形体。总阳性率1.20%;阳性小兽分属3目6科7属12种,分别是:针尾鼹50.00%(1/2)、纹背鼩鼱12.50%(2/16)、珀氏长吻松鼠8.33%(1/12)、藏鼠兔5.66%(3/53)、白尾松田鼠5.41%(2/37)、西南绒鼠4.00%(2/50)、社鼠3.74%(4/107)、大足鼠3.57%(1/28)、斯氏家鼠2.20%(2/91)、大耳姬鼠1.85%(2/108)、中华姬鼠1.30%(4/308)和黄胸鼠0.69%(3/433),分布于5个县(市)。统计学分析表明,无形体的感染率雄性高于雌性,海拔>2 500 m捕获小兽感染率最高。不同生境和年龄的小兽感染率无差异。结论 云南省部分县(市)的多种小型兽类携带A.phagocytophilum,给当地人群的健康和畜牧业的发展造成一定的威胁,人群和媒介蜱、其它宿主的感染和分布等情况值得进一步关注。

Molecular epidemiological survey of Anaplasma in small mammals in Yunnan province

To investigate the species and epidemic situation of Anaplasma infecting small mammals and survey the threat to the human and domestic health in Yunnan Province and provide scientific evidence for developing control measures. A total of 2 251 small mammals belonging to 52 species, 26 genera, 9 families from 4 orders were captured in 130 sample locations in 22 counties of Yunnan Province. DNA was extracted from spleen tissue. A nested PCR to target partial sequences(660 bp) within the 16S rRNA gene of Anaplasma was done by using universal primers of Anaplasma. Anaplasma species was identified by Blast program and phylogenetic tree. Epidemiological significance was analyzed by knowing Anaplasma species and sample information. 27 samples were infected with Anaplasma with the infection rate of 1.20%, of which 23 were infected with Anaplasma phagocytophilum, 4 were infected with Anaplasma sp. These positive small mammals belonging to 12 species,7 genera and 6 families from 3 orders were S. fusicaudus (50.00%), S.cylindricauda (12.50%), D.pernyi (8.33%), O. thibetana (5.66%), P.leucurus (5.41%), E.custos (4.00%), N.confucianus (3.74%), R. nitidus (3.57%), R. brunneusculus (2.20%), A.latronum (1.85%), A.draco (1.30%) and R.tanezumi (0.69%). The positive samples belonging to 12 species, 7 genera, 6 families from 3 orders originated from 5 counties. The prevalence of Anaplasma in male small mammals was significantly higher than that in the female mammals. The prevalence of A.phagocytophilum in small mammals at the altitude classes of >2 500 meters were highest. However, there was no significant difference in prevalence of A.phagocytophilum between different mammal genders, as well as ages.Conclusion Many species of small mammals in some counties of Yunnan Province were infected with A.phagocytophilum, which threaten human health and stock raising development. It is necessary to investigate infection rate of Anaplasma in ticks, humans and other host animals.