Mechanical transmission of Dengue Virus by Aedes aegypti may influence disease transmission dynamics during outbreaks

The escalating number of dengue virus (DENV) outbreaks and their worldwide spread pose a major threat to global public health. DENV transmission dynamics significantly influence outbreak duration and magnitude. Conventional DENV transmission requires an incubation period between mosquitoes biting infected humans and the mosquitoes becoming infectious. However, the possibility of immediate, mechanical transmission of DENV without viral replication in the mosquito has received little attention despite its potential importance. Here, we show that Aedes aegypti mosquitoes can mechanically transmit DENV to susceptible mice immediately after biting infected mice without the need for an incubation period. By incorporating parameters from our experiments into a newly developed mathematical model, we found a significant impact on DENV outbreak characteristics. Mechanical transmission may amplify existing disease transmission routes and influence outbreak dynamics. Our findings have implications for vector control strategies that target mosquito lifespan and suggest the possibility of similar mechanical transmission routes in other disease-carrying mosquitoes.