A recent study funded by the Swine Health Information Center underscores the significant threat Japanese encephalitis virus (JEV) poses to the global swine industry. The study, led by Dr. Natalia Cernicchiaro at Kansas State University, in collaboration with USDA Agricultural Research Service scientists at the National Bio and Agro-Defense Facility, included a systematic literature review and meta-analysis on JEV vector and host competence. Key findings from experimental studies reveal that at least nine additional mosquito species can be potential vectors for JEV, nearly half of the mosquitoes exposed to JEV became infected, and that one in four infected mosquitoes can transmit JEV to hosts. Culex species of mosquitos may pose the greatest risk to humans and animals, including swine. Findings emphasize the need for robust surveillance and integrated mosquito management strategies for US pork producers.
The full report published by Parasites & Vectors can be accessed here.
Japanese encephalitis is an emerging zoonotic disease transmitted by JEV-infected mosquitos. It is considered a significant human and animal health threat. The virus is primarily maintained in its natural life cycle between mosquitoes and waterbirds, while occasionally spilling over into swine, horses, and humans. JEV infections in swine result in reproductive disease outcomes on sow farms, such as stillbirths, mummified fetuses, and abortions. While JEV has not been detected in the US, its recent spread globally, coupled with the presence of competent mosquito vectors and susceptible hosts in the US, elevates the risk of incursion.
Considering the recent expansion of JEV into mainland Australia and increased global research activity, this systematic review summarizes new experimental data on mosquito vector competence published between 2016 and 2023, building on a 2018 review previously published by the investigators. All reports included in the review were peer-reviewed literature and screened for relevance to vector competence, with a focus on JEV infection, dissemination, and transmission rates as the primary outcomes of interest. The study population was limited to mosquito vectors, and only experimental studies were eligible.