Dynamics of plague epidemic in Spermophilus alaschanicus plague foci of Gansu Province from 1962 to 2018 / 中华地方病学杂志

ABSTRACT

Objective:To analyze the dynamics of plague epidemic in Spermophilus alaschanicus plague foci of Gansu Province from 1962 to 2018, and to provide evidence for plague control and prevention. Methods:The data of Spermophilus alaschanicus plague in Gansu Province from 1962 to 2018 were collected and organized from epidemic surveillance and epidemic summary. The method of descriptive epidemiology was used to analyze plague, including population (regional distribution, time distribution) and animal (geographic distribution, infected animals and vectors) epidemiology. Results:There was only one case of human plague in the Spermophilus alaschanicus plague foci of Gansu Province from 1962 to 2018. The total incidence of the disease was 26 cases, 11 cases died, the incidence rate was 29.89% (26/87), and the mortality was 42.31% (11/26). The cases were mainly distributed in Liuzhai Township and Xinyuan Township of Huining County. The outbreak occurred from July to August. Plague bacteria were isolated from the plague foci of Gansu Province during two peak epidemics of the plague among animals from 1962 to 2018. The bacteria detection area was located in 2 rural areas that were the northern area of Liuzhai in Huining County, and the neighboring Zhongtian and Fuxing in Pingchuan District. Five places were determined to be the animal epidemic sites. The endemic species were Spermophilus alaschanicus and Vulpescorsac, and the vector species were Citellophilus tesquorus mongolicus and Neopsylla abagaitui. The epidemic time of animal plague was from April to August. Totally 115 positive serum F1 antibodies were obtained. Among them, 92 positive serum samples were detected in Huining County and 23 in Pingchuan District. The positive blood coagulation sites were distributed in 11 villages, 5 towns of 2 counties (districts). The surveillance results showed that 30 species of animals belonging to 5 orders, 11 families, 5 subfamilies, and 21 genera were found in the foci, most of them were Spermophilus alaschanicus, which accounting for 69.1% (2 464/3 567) of the total species of rodents in the past years. A total of 12 482.9 hm 2 were investigated by sampling method, and 9 709 Spermophilus alaschanicus were captured, with an average density of 0.78/hm 2. Conclusions:The plague is intermittently prevalent in Gansu's Spermophilus alaschanicus plague foci. So the prevention and control strategies should be adjusted in time according to the changes. In residential areas, we should take the initiative to strengthen the monitoring of rat situation and the publicity and education of human plague prevention knowledge.