Understanding arbovirus transmission between an infected vector and host is critical for forecasting and control of arboviral outbreaks. While much focus is on vector competence and the ability of vectors to transmit a virus under laboratory conditions, transmission from vector to host in the field is a process that has received little attention. By examining spatial and temporal conditions associated with arbovirus transmission we may identify predictors of transmission indices. We monitored field sites in three counties in Florida, where we trapped weekly during the 2005 arbovirus transmission season using chicken baited traps. This enables us to examine both infection rates in mosquito pools as well as transmission rates of the virus to chickens. Mosquitoes were pooled by species and tested for West Nile virus (WNV) and St. Louis encephalitis virus (SLEV). Chicken sera are currently being tested for antibodies to both arboviruses. Out of 4009 pools collected, a total of 23 mosquito pools were positive for either WNV (20 pools) or SLEV (3 pools). Infected pools were collected in all three counties and consisted of five different species of mosquito, predominantly Culex nigripalpus. Associations of virus isolations from mosquitoes and seroconversions in chickens will be discussed as well as the implications of transmission from vector and host. This research enables a more complete understanding of the field dynamics of arboviral transmission, including factors that may enhance or suppress transmission. Increasing our understanding of this cycle will allow for a greater ability to predict and control arboviral outbreaks.