Is the U.S. pork industry prepared for a Japanese encephalitis virus (JEV) outbreak? A recent economic assessment shows this transboundary emerging disease risk for the U.S. could result in potential economic implications greater than $500 million. That’s why the Swine Health Information Center (SHIC) says it’s critical to establish a reliable way to detect JEV in swine samples prior to an introduction or outbreak.
JEV is transmitted by the bite of infected mosquitos and can cause severe disease in pigs, horses and humans. Although it’s historically endemic to Asian and western Pacific regions, the 2022 JEV outbreak in Australia raised concerns of a renewed threat to the U.S. pig industry and public health.
In a SHIC-funded project, principal investigator Rahul Nelli and co-investigator Phil Gauger of Iowa State University, established RT-rtPCR assays for JEV and its five genotypes, comparing the newly established test with a previously published assay in the process.
“Development of a JEV test for U.S. veterinary diagnostic labs that can accurately and efficiently detect multiple JEV genotypes will help the U.S. pig industry monitor and respond rapidly to a potential JEV incursion,” SHIC says. “A potential outbreak of JEV in the U.S. pig population can have detrimental economic and public health impacts. It is crucial to be vigilant and establish a screening method to detect the virus early when clinical signs suggest that JEV could be a differential diagnosis.”
Findings from this project suggest
- The newly developed novel RT-rtPCR assay is more specific than previously published assays and can detect all five JEV genotypes (G-1, -2, -3, -4, -5) accurately and efficiently.
- The new assay also has a low detection limit, meaning it can detect very small amounts of the virus.
- The project confirmed that the novel JEV PCR assay does not cross-react with other viruses endemic to the U.S. swine herd.
- Validation of genotype-specific RT-rtPCR assays and evaluation of assay performance on known status clinical samples in collaboration with Australian swine industry stakeholders is ongoing.
SHIC points out that before the assay developed can be used for routine diagnostics, it must be further validated for diagnostic specificity and sensitivity utilizing the American Association of Veterinary Laboratory Diagnosticians and National Animal Health Laboratory guidelines. A collaborative effort will be undertaken with known status JEV samples from the Australian outbreak.
“This collaborative research aims to ensure that the assay is accurate and reliable in detecting JEV in various conditions and across different clinical samples. By validating the assay using these methods, greater confidence is achieved in its ability to help identify and prevent the spread of JEV in pigs. Early and accurate diagnosis of JEV is crucial for rapid response efforts to reduce the potential disease impact on humans and the production impacts for pork producers,” SHIC says.
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