云南省丽江市古城区鼠疫疫源地噬菌体的分离及鉴定

目的 调查丽江市古城区野鼠鼠疫疫源地宿主动物携带鼠疫噬菌体情况,并探讨其流行病学意义,为野鼠鼠疫疫源地宿主动物的防制提供科学依据。方法 2017年9月于丽江市古城区5个乡镇共13个野鼠鼠疫疫源地的鼠疫流行自然村采用5 m夹线法进行捕鼠,以鼠疫疫苗株EV76为饲养菌（即鼠疫噬菌体的宿主菌）,采用双层平板法分离鼠疫噬菌体,对所分离噬菌体进行噬菌斑观察和电镜下形态鉴定。结果 在丽江古城区5个乡镇共捕鼠766只,其中七河321只,文化镇131只,开南良美48只,大东乡117只,金安乡149只,采集鼠回盲段样本766份,在34份样本中分离34株鼠疫噬菌体,鼠疫噬菌体分离率4.43%;5个乡镇均分离到鼠疫噬菌体,其中七河噬菌体阳性率较高（6.85%）。34株鼠疫噬菌体中,29株分离自齐氏姬鼠,2株分离自大绒鼠,3株分别来自灰麝鼩、斯氏家鼠和树鼩。齐氏姬鼠的噬菌体阳性率显著高于其他鼠种,其所分离鼠疫噬菌体的噬斑出现特大（直径2.5~<3.5 mm）、大（直径1.5~<2.5 mm）、中（直径0.5~<1.5 mm）及小（直径<0.5 mm）四种噬菌斑。结论 丽江市古城区野鼠鼠疫疫源地宿主动物中携带一定数量的鼠疫噬菌体;因齐氏姬鼠的噬菌体携带率远高于其他鼠种,证明齐氏姬鼠是该疫源地的主要宿主。

Isolation and identification of plague phage from plague foci in Ancient District,Lijiang, Yunnan

Objective To investigate whether the host animals carry plague phage of Ancient District in Lijiang, and we explore the epidemiological significance, to provide scientific basis for prevention and control of host animals in plague foci. Methods Rodent specimens from 13 natural villages of 5 townships in the plague foci in Ancient District of Lijiang District were respectively collected, by 5 m clamp method in September 2017. Vaccine strain EV76 was used as breeding bacteria, phage whose plaque morphology and morphology under electron microscope were identified was isolated from the samples, by double-layer plate method. Results Sampling was carried out in 5 village and towns in the Ancient District of Lijiang, and 766 ileocecum samples were collected from 766 rodents (321 in Qihe , 131 in Wenhua Town, 48 in Kainanliangmei , 117 in Dadong Town, and 149 in Jin'an Town), 34 plague phages were isolated with a total positive rate of 4.43%; Yersinia pestis bacteriophages were isolated from all five foci, of which the positive rate of Qihe (6.85%) was the highest. Of the 34 strains , 29 strains were isolated from Apodemus chevrieri, 2 from Eothenomys miletus and 3 from Crocidura attenuata, Rattus sladerni Andenson and Tupaia belangeri respectively. The positive rate of Apodemus chevrieri was higher than others; There were four kinds of plaque morphology: Outsize (2.5-<3.5 mm), large (1.5-<2.5 mm in diameter), medium (0.5-<1.5 mm) and small (<0.5 mm) in plague phage. Conclusion A certain number of plague phages are carried in the host animals of the plague foci in Gucheng District of Lijiang City, and the phage carrying rate of the Apodemus chevrieri is much higher than that of other species, which is the evidence that Apodemus chevrieri is the principal host in the foci. The polymorphism and microecological relationship with Yersinia pestis need to be analyzed in biology and genomics.