Investigating the risk of introduction of the Japanese Encephalitis Virus in the USA
Natalia Cernicchiaro, DVM, MS, PhD
Department of Diagnostic Medicine and Pathobiology
Center for Outcomes Research and Epidemiology
Kansas State University
Japanese encephalitis (JE) is a vector-borne disease transmitted by mosquitoes infected with the Japanese encephalitis virus (JEV) that occurs in Southeast Asia and the Western Pacific. Over 30 mosquito species have been recognized as JEV-competent, mainly from the Culex genus. Competent host species include pigs, the most important JEV amplifying hosts, and ardeid birds. Vectors and hosts interact in complex and dynamic transmission patterns that are either pig- (domestic cycle) or bird-associated (wild cycle). In humans, considered dead-end hosts, JEV causes a debilitating, neurological disease that mainly affects children and immunocompromised individuals. JE has no cure, thus, efforts are put forth towards prevention and control by reducing exposure to potentially infected mosquitoes, or vaccination. Earlier this year, JE was identified as a “communicable disease incident of national significance” in Australia. This notification followed the detection of JEV in mummified, stillborn, and weak newborn piglets from over 50 commercial piggeries across four southern Australian states, with connected recognition of human cases of JE. As of September 8, 2022, a total of 40 confirmed human cases that had led to 6 deaths have been reported. The United States represents a region favourable for potential entry and spread of the virus, having both JEV-competent vectors and hosts, as well as no active JEV surveillance programs currently in place. This presentation will examine findings from recent and ongoing studies from our group regarding the application of epidemiological methods to evaluate vector and host competence for JEV, and to quantify the risk of introduction of JEV in the United States.