Dynamic modelling and analysis of human brucellosis on age heterogeneity in Jinzhou, China

Since brucellosis causes harms and losses to sheep and human populations in the cities of Northern and Northwest China, we establish a cross-species brucellosis model with age-structure and bilinear incidences to characterize brucellosis transmission mechanism in this study. Firstly, the basic reproduction number, the disease-free and endemic equilibrium points of the brucellosis model are obtained. Then, the stabilities of two equilibrium points are proved by Routh-Hurwitz Criterion and LaSalle's Invariance Principle. Precisely, the disease-free equilibrium point is locally and globally asymptotically stable with R ₀ < 1; and the endemic equilibrium point is globally asymptotically stable with R ₀ > 1. Further, the 2017-2023 monthly brucellosis surveillance data from Jinzhou CDC are fitted by the least squares method and EpiSIX, showing that the values of basic reproduction numbers keep high consistency with the known results. The numerical simulations indicate that the reduction of brucellosis transmission risks depend on the decreases of direct transmission rates and recruitment rate, and the increases of culling rate and vaccination rate. Finally, the 2024-2030 yearly tendency predictions under two scenarios indicate that quadruple-control measure provides the extreme brucellosis transmission risks, compared with those from three-type control measures. As a consequence, for the local farmers and policy-makers, some suggestions are proposed to suppress the brucellosis infectious scales for the cities with similar sheep breeding patterns and geographical locations to Jinzhou on the Chinese mainland.