How do interventions impact malaria dynamics between neighboring countries? A case study with Botswana and Zimbabwe
Malaria is a vector-borne disease that is responsible for over 400,000 deaths per year. Although countries around the world have taken measures to decrease the incidence of malaria, many regions remain endemic. Indeed, progress towards elimination has stalled in multiple countries. While control efforts are largely focused at the national level, the movement of individuals between countries may complicate the efficacy of elimination efforts. Here, we consider the case of neighboring countries Botswana and Zimbabwe, connected by human mobility. Both have improved malaria rates in recent years with differing success. We use a two-patch Ross-MacDonald Model with Lagrangian human mobility to examine the coupled disease dynamics between these two countries. In particular, we are interested in the impact that interventions for controlling malaria applied in one country can have on the incidence of malaria in the other country. We find that dynamics and interventions in Zimbabwe can dramatically influence pathways to elimination in Botswana, largely driven by Zimbabwe’s population size and larger basic reproduction number.
