Dynamic interaction between transmission, within-host dynamics and mosquito density.

The central question in this paper is the character and role of the within-host and between-host interactions in vector-transmitted diseases compared to environmental-transmitted diseases. In vector-transmitted diseases, the environmental stage becomes the vector population. We link an epidemiological model for a vector-transmitted disease with a simple immunological process: the effective transmission rate from host to vector, modeled as a function of the infected cell level within the host, and a virus inoculation term that depends on the abundance of infected mosquitoes. We explore the role of infectivity (defined as the number of host target cells infected), recovery rate, and viral clearance rate in the coupled dynamics of these systems. As expected, the conditions for a disease outbreak require the average individual in the population to have an active (within-host) viral infection. However, the outbreak's nature, duration, and dynamic characteristics depend on the intensity of the within-host infection and the nature of the mosquito transmission capacity. Through the model, we establish inter-relations between the infectivity, host recovery rate, viral clearance rate, and different dynamic behavior patterns at the population level.