Modeling the Infection of Multiple Strains of Dengue Virus Within a Mosquito

Mathematical modeling has become an important tool in understanding the spread and persistence of infectious diseases. In multi-strain pathogens, such as dengue virus, understanding within-host infection dynamics is increasingly important to better inform transmission dynamics at the between-host level. Until recently, research in this area has primarily focused on the interaction of pathogen strains within vertebrate hosts, but neglected to consider key interactions within invertebrate vectors. Using the dengue virus and its mosquito vector, Aedes aegypti, as a case study, we develop a within-vector mathematical model of infection dynamics. Our differential equation model specifically considers virus dynamics both within the midgut and the salivary glands of the mosquito. An infection can only be transmitted to a vertebrate if a virus strain can escape the midgut barrier and replicate within the salivary glands. We use our model to ask how competition between strains within a mosquito affects transmission of the virus to humans. We also examine whether mosquitoes could transmit multiple strains simultaneously, which could partially explain recent data on human co-infections.