Changing trends in human brucellosis in pastoral and agricultural China, 2004-2019: a Joinpoint regression analysis.

Abstract

Background: The incidence of human brucellosis has risen sharply in China but little is known about trends in pastoral and agricultural areas respectively. This study aimed to analyze the annual and monthly incidence trends of human brucellosis in China from 2004 to 2019. It sought to identify factors contributing to higher incidence rates at specific times and to compare incidence trends across pastoral, agricultural/pastoral, and agricultural areas.

Methods: Annual and monthly incidence and numbers of reported cases of human brucellosis in regional China between 2004 and 2019 were accessed from the National Public Health Science Data Sharing Center, and the annual percentage change (APC) in pastoral and agricultural areas was calculated. Annual and monthly trends were analyzed by the Joinpoint regression model.

Results: 569016 cases of human brucellosis were reported between 2004 and 2019 with a peak in 2014. A trend of increasing incidence was found (AAPC = 6.3%, 95% CI: 3.2-9.4%) with higher rates in pastoral areas but greater mean increases in agricultural (AAPC = 9.4) and agricultural/pastoral areas (AAPC = 7.7) than in pastoral areas (AAPC = 5.9). Infections occurred throughout the year with a concentration of cases between March and July. Increasing monthly incidence was found in all types of areas from January to May (APC > 0) and a decreasing monthly trend was seen from May to December (APC < 0, p < 0.05).

Conclusions: The incidence of human brucellosis was higher in pastoral areas of China than in agricultural/pastoral or agricultural areas, however, the rate of increase was higher in agricultural/pastoral and agricultural areas than in pastoral areas. Epidemic surveillance should be strengthened in key areas and prevention and control measures increased nationwide.