Surveillance and analysis on plague natural foci in Yanchi County of Ningxia Hui Autonomous Region from 1970 to 2019
Objective To analyze the monitoring and investigation data of animal plague in Yanchi County of Ningxia from 1970 to 2019,and provide scientific guidance for the prevention and control of natural foci diseases in this area.Methods The density of the main hosts of plague was investigated by the pit clip method,and the density of nocturnal rodents by 5 m-clip method;The parasitic fleas were investigated by combing the surface of the rodents;Rodents blood was taken for pestis serological test;Data of the plague survey in Yanchi County from 1970 to 2019 were collected and analyzed.Results The annual average density of Meriones unguiculatus was 2.62/hm2 from 1970 to 2019,with the density fluctuations between 0.48 and 40.59 per hm2.The total average capture rate of nocturnal rodents in the survey was 7.57%.The capture rate of small rodents fluctuated between 3.13%and 15.26%.The average flea infection rate of rodents was 20.28%,with the fluctuation between 5.51%and 66.42%in the years;the general flea index was 0.42,fluctuated between 0.16 and 1.46.A total of 267 strains of Yersinia pestis were detected out,233 from animals and 34 from vectors.49 rodents the serological tests were positive,with the positive rate of 0.27%.Conclusion The epidemic of animal plague in Yanchi County was distributed in Huamachi Town,Gaoshawo Town and Wanglejing Township,and the core area was in Huamachi Town.There were 10 annual epidemics of plague among animals,with obvious intervals,the longest as 16 years and the shortest as 4 years.
the natural focusanimal plagueflea indexYersinia pestis