Identification of a One Health Intervention for Brucellosis in Jordan Using System Dynamics Modelling

Brucellosis occurs because of a complex multisector system involving the interplay between animal production and human behavior. A better understanding of transmission dynamics helps pinpoint the most effective interventions to reduce human and animal cases. Modeling methodologies have not been applied extensively to brucellosis. This study applies system dynamics modeling to identify the interplay between the different sectors that drive disease transmission and identify One Health interventions to control brucellosis. The study applies a quantitative system dynamics modeling methodology based on a qualitative in-depth analysis of the Brucella transmission system in Jordan. The data are analyzed manually to establish causal pathways to develop a stock and flow (SF) model. The structure is examined and reviewed by key informants. Several intervention scenarios to control Brucella transmission is assessed. Brucella transmission among sheep and between farms and markets are the main drivers of human incidence. Farmers' visits to veterinary clinics are a critical intervention point for control associated with access to vaccination. The vaccination of sheep and health education activities alone might not be an effective strategy. Testing and culling sheep is the most efficient individual control strategy for animal incidence and a combination of public and animal health strategies (One Health) is the most effective strategy to reduce human incidence. The synthesis of current knowledge through the system dynamics model enables better understanding, visualization, and interpretation of the sectors involved in Brucella transmission. There is a strong synergy between sectors; therefore, greater control might be provided by utilizing multi-sectoral relationships embedded in the system.