Isolation and epidemiological significance of <italic>Yersinia pestis</italic> phages in indicator animals from the house mouse plague foci of Yunnan Province

Youhong Zhong; Chao SU; Biao Duan; Yibo Ding; Qingchun DU; Cunjuan Duan; Danni Zhao; Wei LI; Peng Wang; Hesong WU

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Isolation and epidemiological significance of Yersinia pestis phages in indicator animals from the house mouse plague foci of Yunnan Province

VernacularTitle: 云南家鼠鼠疫疫源地指示动物中鼠疫噬菌体分离及其流行病学意义
Author: Youhong ZHONG ¹ ; Chao SU ¹ ; Biao DUAN ¹ ; Yibo DING ¹ ; Qingchun DU ² ; Cunjuan DUAN ¹ ; Danni ZHAO ² ; Wei LI ³ ; Peng WANG ¹ ; Hesong WU ¹
Author Information

1. Yunnan Provincial Key Laboratory for Zoonosis Control and Prevention, Yunnan Institute for Endemic Disease Control and Prevention, Dali 671000, China
2. Department of Epidemiology and Health Statistics, School of Public Health, Dali University, Dali 671000, China
3. State Key Laboratory for Infectious Disease Prevention and Control, Institute for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, Beijing 102206, China
Publication Type:Journal Article
Keywords: Plague foci; Indicator animals; Phage of Yersinia pestis; Epidemiological significance
From: Chinese Journal of Endemiology 2019;38(11):861-867
CountryChina
Language:Chinese
Abstract: Objective:To investigate whether plague phages were present in the indicator animals of plague foci in Yunnan Province, and to explore their epidemiological significance.
Methods:Anus swabs were collected from indicator animals (dogs or cats) of the 41 plague affected villages in 26 towns of 10 cities (counties, districts) of Yunnan plague foci from November of 2015 to March of 2018. The Yersinia pestis phages were isolated by plague vaccine strain EV76. The isolation of plague phages from different plague foci, the isolation of plague phages from different canine species (cats), the polymorphism of plaque and the host spectrum of phages were analyzed.
Results:A total of 1 014 indicator animals (1 003 dogs and 11 cats) were studied, and 102 of plague phages were isolated. In the 10 cities (counties, districts), plague phages were only not isolated from Lancang County, and the plague phages were isolated from the other 9 cities (counties, districts). The separation rates from high to low were as follows: Yiliang County (21.00%, 21/100), Menghai County (19.23%, 25/130), Yuanjiang County (11.63%, 10/86), Midu County (11.50%, 13/113), Wenshan County (10.10%, 10/99), Mile Country (7.07%, 7/99), Lianghe County (6.67%, 7/105), Baoshan Longyang District (4.90%, 5/102) and Gengma County (3.81%, 4/105). Of the 102 plague phages, 75 were isolated from the native dogs (Chinese pastoral dogs, 9.32%, 75/805), 20 from the pug dogs (13.70%, 20/146), 5 from the wolf dogs (17.24%, 5/29), 1 from Samoye (1/4) and 1 from Alaska dog (1/2). The plaque of the phage was divided by five appearance of complete lysis (the plate was clear), large (2.5-4.0 mm), big (1.5-< 2.5 mm), middle (0.5-< 1.5 mm) and small (< 0.5 mm). The representative phages were all of the Myoviridae family. Most of the phages could lysis the strains of Yersinia pestis, and some phages could lysis Shigella and type 5 Yersinia pseudotuberculosis (PST5).
Conclusion:The plague phages are present in the plague foci of Yunnan, and the phages are polymorphic.