“We need to be prepared”: test developed for Japanese encephalitis virus

When porcine epidemic diarrhea virus (PEDV) struck U.S. pig herds in 2013, the Iowa State University (ISU) Veterinary Diagnostic Laboratory (VDL) – which carries the nation’s largest swine caseload – scrambled to design a high-capacity test to keep up with the outbreak. Then they had to play a little catch-up to manage the large caseload, which taught the researchers many lessons.

It’s part of the reason VDL researchers have developed a diagnostic test for swine to detect Japanese encephalitis virus (JEV), a mosquito-borne disease common in southeast Asia that hasn’t been seen in the US.

JEV became a higher priority after it spread to Australia in 2022, prompting the Swine Health Information Center – a pork checkoff-funded industry organization charged with monitoring swine diseases – to fund development of a real-time polymerase chain reaction (PCR) test for JEV, the same genetically based screening method considered the gold standard for diagnosing COVID-19.

Having a federally approved JEV test ready would help mitigate the damage of a possible outbreak, which could cause a drop in U.S. pork production of 1-2% and lead to economic losses of up to $612 million, according to an estimate commissioned by the Swine Health Information Center.

While most cases of JEV in pigs lead to minor symptoms, it can cause neurological and reproductive issues. JEV also poses risks for other animals, including humans. Severe symptoms in infected humans are rare, but in the 1 in 250 cases where they develop, the fatality rate is as high as 30%, according to the World Health Organization. The test developed at Iowa State, which can detect all five genotypes of JEV, could be used for humans, said Rahul Nelli, head of the research project.