Bosco-Lauth, Angela M., authorBowen, Richard, advisorQuackenbush, Sandra, advisor2024-03-132024-03-132010https://hdl.handle.net/10217/237593Japanese encephalitis virus (JEV) is a vector-borne disease of Asian origin that has the potential to spread into temperate regions across the globe. The recent incursion of the virus into Northern Australia illustrates its ability to replicate in different vectors and has led to an increase in the need for disease surveillance in the U.S. and other locations. The focus of this dissertation was to investigate the potential of some common North American mosquitoes to transmit JEV and to study the pathogenesis and immunity in animal models, namely horses and hamsters.Four mosquitoes were tested for JEV vector competence: Culex tarsalis, Culex pipiens, Aedes aegypti, and Aedes albopictus. Both Culex species and Aedes aegypti can become infected with the virus through an artificial blood meal and will replicate and disseminate the virus over several weeks time. Mosquitoes with a disseminated infection can then transmit the virus back into blood meal during feeding, thus demonstrating the capacity to infect a host while feeding.Horses, like humans, are incidental hosts for JEV and can develop severe neurological deficits and in some cases die from an infection. Pathogenesis of the virus in horses as well as their potential role in the virus replicative cycle has not been clarified experimentally. The experiments in this thesis revealed that Aedes aegypti mosquitoes can transmit JEV to horses and that horse infection results in low level viremia. Mosquitoes allowed to feed on viremic horses failed to become infected, thus confirming the likely role of horses as dead-end hosts. Three of six horses developed viremia, two with mild pyrexia, but no clinical or post-mortem pathological findings suggested the development of encephalitis.Pre-existing immunity to related flaviviruses such as West Nile virus (WNV) is thought to produce some protective effect against JEV infections. Prior immunization or infection with live flaviviruses within the JEV serocomplex of viruses, including WNV and St. Louis encephalitis virus (SLEV), protected Golden Syrian hamsters from JEV infection. Immunization with recombinant or DNA vaccines for WNV has a reduced protective effect, suggesting that humoral immunity is best derived from active viral infections.The results of these studies provide some insight into potential vectors of JEV in North America and elucidate some of the mechanisms of viral pathogenesis and immunity in mammals. The overall purpose is to demonstrate a need for emerging disease surveillance for JEV in the U.S. and to try to predict what amount of spread could be reduced by prior immunity to WNV or SLEV.born digitaldoctoral dissertationsengCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.hamstershorsesimmunityJapanese encephalitis viruspathogenesisvector competencemicrobiologyvirologyTextPer the terms of a contractual agreement, all use of this item is limited to the non-commercial use of Colorado State University and its authorized users.