Surveillance for brucellosis in human and livestock in Gansu, 2021−2022

Objective To understand the epidemiological characteristics of brucellosis in human and livestock in Gansu province from 2021 to 2022 and provide reference for the development of future prevention and control measures.

Methods The incidence data of brucellosis in human and livestock in Gansu from 2021 to 2022 were used to establish a database with Excel. Descriptive epidemiological method was used to analyze the distribution of human brucellosis and the changing characteristics of the infection in livestock.

Results From 2021 to 2022, a total of 9 830 cases of human brucellosis were reported in Gansu, the differences in the incidence among different years were significant (χ²=42.941, P<0.05). During this period, a total of 27 875 livestock were reported positive for Brucella in Gansu. Brucellosis occurred all the year round. The incidence of human brucellosis peaked during June-July, and the highest case count was in age group 50–59 years (3 550 cases), accounting for 36.11%, and the male to female ratio of the cases was 2.67∶1. The cases in farmers accounted for 87.92% of the total (8 643/9 830), followed by herdsmen (231 cases, 2.35%), students (198 cases, 2.01%), the unemployment or jobless (197 cases, 2.00%) and workers (103 cases, 1.05%). The top 6 areas with high incidence of human brucellosis for two consecutive years were Zhangye, Jinchang, Jiuquan, Baiyin, Qingyang and Linxia, the differences were significant (χ²=41.259, P<0.05). The top 7 areas with high counts of infectious livestock were Qingyang (20 574), Zhangye (2 465), Jiuquan (1 650), Baiyin (1 229), Dingxi (528), Jiayuguan (506) and Lanzhou (42). There were three positive livestock species, sheep, cattle (cow and others), and camel. In the 27 858 Brucella positive samples detected in livestock, 27 358 were detected in sheep (98.15%), 255 in cows (0.92%), 78 in other cattle (0.28%), 184 in camels (0.66%).

Conclusion The incidence of human brucellosis in Gansu continued to increase, but the disease mainly occurred sporadically. The positive rate of Brucella in livestock continued to decline, and the incidence trend in human and livestock was opposite in some areas. It is necessary to strengthen source control, epidemic surveillance, health education, and behavioral intervention in key groups, and strictly implement comprehensive prevention and control measures.