Microtus fuscus plague natural foci surveillance results in Sichuan, 2013−2020

  Objective  To analyze the changing trends of the Microtus fuscus plague natural foci in Sichuan province and provide reference for the prevention and control of plague.

  Methods  According to “National Plague Surveillance Protocol” and “Sichuan Province Plague Surveillance Protocol”, continuous surveillance for host animals, vectors and pathogens in the Microtus fuscus plague natural foci in Sichuan were conducted. Descriptive epidemiological method was used to analyze Microtus fuscus plague natural foci surveillance data in Sichuan from 2013 to 2020.

  Results  From 2013 to 2020, a total of 5007 Microtus fuscus and 283 nocturnal mice were captured. The rodent density of Microtus fuscus ranged from 113.14 to 123.81 perhectare. The flea infection rate was 58.46%, the average flea index was 0.95, and the nest flea infection rate was 100%, the nest flea index was 70.03. The main fleas seized were Chrysosphaeria gracilis and Amphiprion. A total of 25 strains of Yersinia pestis were isolated and 13 positive serum samples were detected.

  Conclusion  From 2013 to 2020, the status of host animals and fleas in the Microtus fuscus plague natural foci in Sichuan were relatively stable, the epidemic of plague among animals was active, and there was a risk of spread of the epidemics in animals to humans and wider spread of plague. It is necessary to continue the plague surveillance in season when Microtus fuscus activities are frequent.