A system dynamics approach to quantifying the cost-effectiveness of endemic livestock disease control: An application to foot-and-mouth disease in Rwanda

CONTEXT: Many livestock diseases persist as endemic processes rather than as isolated outbreaks. These diseases affect herd dynamics, production, economic outcomes. In such settings, livestock systems evolve through interdependent interactions between population demography, disease transmission, and control interventions. However, most epidemiological-economic models are oriented toward episodic disease shocks and short-term containment, which limit their usefulness for policy analysis under persistent disease pressure. OBJECTIVE: This study develops and applies an epidemiological-economic modeling framework to assess the long-term impacts of endemic livestock diseases such as FMD on herd populations, production, and economic outcomes, as well as the cost-effectiveness of alternative disease control strategies. METHODS: A system dynamics-based herd dynamics model was linked with an endogenous compartmental disease transmission model to simulate two-way feedback between herd demography, endemic disease spread, and production outcomes over two decades. The framework captures births, natural and disease-induced mortality, productivity losses, and intervention effects under sustained disease pressure. Public-sector intervention costs were incorporated into a benefit-cost analysis to compare vaccination, quarantine, and combined vaccination-quarantine strategies. RESULTS AND CONCLUSIONS: Simulation results indicate that endemic disease can substantially affect herd growth, meat and milk production, and economic returns over time. In the absence of control, herd size is 24% lower by the end of the simulation period, while meat and milk production decline by approximately 20% and 18%, respectively, relative to the most effective control strategy (combined vaccination-quarantine). Although combined vaccination and quarantine reduce infections by more than 65% and generate the largest gains in population and production, lower-cost interventions such as quarantine alone produce higher benefit–cost ratios (46.34). The results show clear trade-offs between epidemiological effectiveness and economic efficiency that emerge in long-run, system-level analyses. SIGNIFICANCE: By modeling endemic disease dynamics alongside herd demography and economic outcomes, this study provides an epidemiological-economic analysis of livestock systems beyond outbreak-focused approaches. The framework is adaptable to other endemic livestock diseases, production systems, and country contexts where persistent disease pressure constrains productivity and where policy decisions require balancing long-term health outcomes with limited resources.