This proposal is for an R21, Expanding xenosurveillance capabilities in Central America. The project is a highly multidisciplinary effort that includes collaborators with expertise in virology, public health entomology, surveillance, and human clinical and veterinary medicine. Our study is based on the idea that mosquitoes can serve as surveillance tools because they are essentially autonomous blood sampling devices. Freshly fed mosquitoes are collected from within dwellings and blood is used for surveillance purposes. If successful, our work would have the impact of simplifying certain types of surveillance that require human blood because although most people hate it when they and their children are stuck with needles, they don?t seem to mind mosquitoes being removed from within their homes. In addition, our approach has the potential to make sampling from animals safer by vastly reducing the need for direct contact with fearful and angry animals that bite, kick, etc.. Aim 1 focuses on validating xenosurveillance through a direct comparison to human-based syndromic surveillance. Aim 2 is designed to maintain the scientific rigor of our work by obtaining quantitative estimates of the sensitivity of Cx. quinquefasciatus and Ae. aegypti for xenosurveillance. This proposal leverages significant prior work on xenosurveillance that has focused on An. gambiae in W. Africa, and an ongoing pilot study of xenosurveillance in rural Guatemala.