Objective:To analyze the distribution and epidemic trend of human plague in Yunnan Province from 1950 to 2018, and to provide basis for prevention and control of the plague.Methods:The epidemic data of plague in Yunnan Province from 1950 to 2018 were from the epidemic surveillance and summary data of Yunnan Institute for Control and Prevention of Endemic Disease over the years, and from "the Records of Yunnan Institute for Control and Prevention of Endemic Disease". The data were collected and collated, and the descriptive epidemiological methods were used to analyze the epidemic situation, time distribution, regional distribution and population distribution of the plague.Results:From 1950 to 2018, human cases occurred successively in the plague foci of 38 counties (cities, districts) in 10 prefectures (cities) in Yunnan Province, with a total of 3 463 confirmed cases and 637 deaths, which could be divided into two epidemic cycles: the end of recent history epidemic period (1950-1955) and the relapse epidemic period (1982-2005). The case fatality rate of human plague in the plague foci of domestic plague in Yunnan Province was 18.00% (615/3 416), and that of wild rodents plague was 46.81% (22/47), the difference was statistically significant (χ 2=25.267, P < 0.01). At the end of recent history epidemic period, the case fatality rate was 21.46% (633/2 950), and 0.78% (4/512) at the relapse epidemic period, the difference was statistically significant (χ 2=124.478, P < 0.01). Of the 513 cases diagnosed after 1986, the epidemic season was mainly from July to November (441 cases), and the population was generally susceptible, mostly in people aged 15-45 years old (217 cases). Conclusions:The epidemic scope of human plague in Yunnan Province is relatively wide, and shows the periodicity of epidemic-rest-re-epidemic-re-rest, which generally shows a downward trend. However, due to the persistence of the epidemic focus, the prevention and control of human plague still needs to be paid attention.

Objective: To analyze the epidemic trend of the domestic rodents plague natural foci among animals in Yunnan Province, so as to provide a basis for formulating plague prevention and control strategies. Methods: Monitoring and summarizing data of plague epidemic situation in Yunnan Province from 1950 to 2018 were collected from Yunnan Institute for Endemic Disease Control and Prevention. Descriptive epidemiological method was used to analyze the prevalence of plague among animals. Simple linear regression equations were established using SPSS 21.0 software to analyze the correlation between plague epidemics and rat density, dyeing rate and human plague in 1982-2007. Results: From 1950 to 2018, 51 counties (cities) in 12 regions (prefectures) were confirmed to have animal epidemics in Yunnan Province, and 1 722 epidemic spots were found. A total of 7 152 monitoring sites had been set up in 98 counties (cities). From 1950 to 1956, the plague epidemic in Yunnan Province was confined to western Yunnan; the 1957-1981 was the resting period; 1982-2007, the epidemic spread from west and southwest to south, central, southeast and east of Yunnan Province; after 2008 entered resting period again. The epidemic season of plague was mainly from June to November. Simple linear regression equation analysis showed that the regression equation Y = 9.112 + 44.848X between animal plague (Y) and rat density (X) and the regression equation Y = 2.261 + 0.139X between human plague (Y) and animal plague (X) were statistically significant (F = 9.306, 5.371, P < 0.05). Conclusions The epidemic trend of plague among animals in Yunnan Province is a "wave type". There is a correlation between animal plague and rat density and human plague. It is the key to prevent the occurrence of animal plague and human plague by monitoring the plague epidemics in animals.

Objective:To analyze the epidemic situation and influencing factors of plague in Dehong Dai and Jingpo Autonomous prefectures (Dehong) from 1950 to 2019, for the improvement of strategies on prevention and control of the disease.Methods:The epidemic situation and surveillance data of animal and human plague in Dehong prefecture from 1950 to 2019 were collected and analyzed by descriptive epidemiological methods. Multiple linear regression equations were established by SPSS 20.0 software to analyze the relationship between plague among animals and rat density and flea index, as well as the relationship between human plague and plague among animals.Results:In Dehong prefecture, plague experienced a phenomenon of epidemic-resting-epidemic-resting cycle, between 1950 and 2019. During this period, 614 epidemic spots were identified in 36 townships of five counties/cities,. Human plague had been prevalent for 15 years, with 1 153 human cases and 379 deaths involved. Between 1982 and 2019, 261 319 rodents were captured, of which Rattus flavipectus accounted for 70.95%(185 421/261 319). A total of 70 124 fleas were seized with 76.65%(53 752/70 124), xenopsylla cheopis as fleas. The index of fleas and free fleas were 0.57 and 0.22 respectively. A total of 1 577 strains of Yersinia pestis were isolated from 285 091 animal specimens and 418 strains of Yersinia pestis were isolated from 60 119 groups of fleas, with 255 F1 antibody positive samples were detected from 64 157 sera samples. Neither Yersinia pestis nor the outbreak of plague had been noticed since 2008. Correlations between both animal plagues and rat density, as well as human plague and animals plague were noticed from the regression analysis. Conclusions:The epidemics of plague were with long-term and stable nature, in Dehong prefecture. Affected by many factors, plague seemed in a resting period currently. However, we should be reminded that the fact that outbreak of plague may revive at some uncertaint point. Hence in order to prevent human plague, strategies as careful surveillance programs on animals, need to be strenthened.