U.S. Pigs Remain at Risk for Japanese Encephalitis Virus

Swine health experts warn of potential introduction of mosquito-borne disease

Published on Mar. 5, 2026

Got story updates? Submit your updates here. ›

While the United States is currently free of Japanese encephalitis virus (JEV), a mosquito-borne disease that can infect pigs, experts warn that the country remains susceptible to the introduction of this emerging disease priority. Megan Niederwerder of the Swine Health Information Center discussed the threat and preparedness efforts at the American Association of Swine Veterinarians' annual meeting in Las Vegas.

Why it matters

JEV is a zoonotic disease that can be transmitted to humans through infected mosquitoes, posing a public health risk in addition to potential impacts on the pork industry. Maintaining vigilance and preparedness is crucial to prevent the introduction and spread of this emerging disease threat in the U.S.

The details

Japanese encephalitis virus is transmitted by Culex mosquitoes and can infect pigs, which can act as amplifying hosts for the virus. While the U.S. is currently free of JEV, the country is considered a geographic region susceptible to the potential introduction of this disease. Experts are monitoring the situation closely and working on prevention and preparedness activities.

  • The American Association of Swine Veterinarians held their annual meeting in Las Vegas in 2026.

The players

Megan Niederwerder

Swine Health Information Center representative who discussed the JEV threat and preparedness efforts at the AASV annual meeting.

Got photos? Submit your photos here. ›

What they’re saying

“While the U.S. is currently negative for this mosquito-borne virus, it's a geographic region that is susceptible to the introduction of JEV.”

— Megan Niederwerder, Swine Health Information Center (feedstuffs.com)

The takeaway

Maintaining vigilance and preparedness is crucial to prevent the introduction and spread of the emerging Japanese encephalitis virus threat in the United States, which could impact both public health and the pork industry.