Identifying critical driving factors for human brucellosis in Inner Mongolia, China

At present, the prevention and control situation of human and animal brucellosis in China is grim and complex. Given the current epidemic situation, prevention and control difficulties, and actual needs of brucellosis, investigating the key environmental factors of human brucellosis is helpful for the effective prevention and control of the disease. The research aims are to understand what factors are driving the changes in human brucellosis. We establish a compartmental model to explain the periodic transmission dynamics of brucellosis, then evaluate the effective reproduction number, and quantify the brucella in the environment of Inner Mongolia from January 2016 to December 2020. The step-wise regression is used to determine the possible factors that are significantly correlated with the incidence of human brucellosis and brucella-contaminated environment, meteorological factors. Machine learning methods random forest and Xgboost are used to capture the relative importance of factors with statistical significance. The results show that multiple driving forces contribute to the transmission of human brucellosis, including the brucella-contaminated environment and meteorological factors. The brucella-contaminated environment accelerates the risk of human brucellosis, and clearly and strongly explains changes in the incidence of human brucellosis in Inner Mongolia. The impact of meteorological factors is indispensable, especially those with time delay. There is a significant correlation between precipitation, relative humidity, atmospheric pressure, and human brucellosis in Inner Mongolia. The proposed models aid surveillance and the early control of human brucellosis outbreaks.