Predicting Japanese Encephalitis Spillover Risk in the United States - Japanese Encephalitis virus (JEV) is a mosquito-borne virus that is a major cause of human viral encephalitis in Asia, with upwards of 65,000 cases occurring annually. JEV is found in a transmission cycle between waterbirds, swine, Culex spp. mosquitoes and incidental hosts of people and animals. JEV has recently begun to spread to new areas such as Australia. JEV risk is of great importance given the incursion of vector-borne diseases like West Nile virus, Zika virus, and Chikungunya virus into new regions. Across the globe temperature is increasing and mosquito-borne diseases are uniquely responsive to such increases. As a result, assessing transmission of vector-borne diseases across temperatures is crucial. The intersection of competent vectors, susceptible hosts, and suitable environments has been linked to emerging vector-borne diseases. Predicting the likelihood of contact and transmission between hosts found in the US is key to estimating JEV risk. To address this critical gap, I seek to develop a spillover model of JEV risk in the US. Researchers developed a framework for modeling R0 based on empirical data from mosquito life history experiments to estimate the suitability for pathogen transmission across temperatures. Such models exist for numerous mosquito-borne diseases, but data on JEV transmission across temperature is lacking. Likewise, spillover models that attempt to incorporate the full suite of ecological and demographic drivers of transmission of zoonotic vector-borne diseases have been developed for other pathogens, yet despite its spillover potential, JEV has yet to be investigated in this holistic framework. In this proposal I will address these gaps through distinct but interconnected aims, leveraging vector biology and computational modeling to: 1) Experimentally measure the effect of temperature on JEV infection and transmission in multiple US vector species and virus genotypes, 2) Evaluate temperature suitability for JEV transmission across the US, 3) Develop mechanistic spillover models to predict JEV risk using amplifying and reservoir host distributions, along with other climatic and ecological information, across the US. In summary, I propose to develop a mechanistic model of JEV spillover in the US, utilizing a One Health approach, accounting for vector, amplifying, reservoir, and incidental hosts found in the transmission cycle of JEV. The emergence of zoonotic diseases has increased. We can prepare for the emergence of future pathogens by synthesizing data across multiple scales to gain a holistic understanding of transmission dynamics by incorporating climatic and zoonotic drivers. The proposed research will expand our understanding by providing novel empirical data necessary to predict JEV risk under different temperature scenarios and identify high-risk areas in the US. Overall, this project has the potential to contribute to new insights into the transmission dynamics of zoonotic diseases and the risk of spillover.
