New findings from The Ohio State University suggest that pigs may serve as a conduit for transmitting the rat strain of the hepatitis E virus (HEV) to humans, potentially through pork products. This revelation underscores the necessity of careful food safety measures and further research on the virus.
New research from The Ohio State University suggests that pigs could be a vehicle for transmitting a strain of hepatitis E virus (HEV) commonly found in rats to humans. This strain, known as rat HEV, has already been responsible for infecting at least 20 individuals globally since the first human case was identified in a person with a suppressed immune system in Hong Kong in 2018.
Though rat HEV is primarily hosted by rodents, the newly identified route of pig transmission may have critical implications for food safety practices globally. Unlike previous human cases of the virus where exposure to rats was not reported, the commonality of pork consumption could be a more plausible transmission pathway.
In a study published in PNAS Nexus, the researchers demonstrated that a strain of rat HEV isolated from humans was capable of infecting pigs and subsequently spreading among them.
“We always want to know which viruses might be up and coming, so we need to know the genetics behind this virus in the unlikely event something happens in the United States that would enable rat HEV to expand,” senior author Scott Kenney, an associate professor of veterinary preventive medicine at Ohio State, said in a news release.
Hepatitis E remains the leading cause of acute viral liver infection worldwide, predominantly affecting regions with poor sanitation. Significantly, the virus is also endemic in pigs within the United States, though it is typically found in the liver and destroyed during cooking. However, the risk of cross-species transmission adds a new dimension of concern, particularly for individuals with compromised immune systems.
The researchers, led by Kush Yadav, tested the capabilities of the LCK-3110 strain, constructing an infectious clone that replicated successfully in various human and mammal cell cultures and in pigs. Viral particles were detected in the blood and feces of pigs a week after exposure to the virus, and by the second week, even non-inoculated co-housed pigs began shedding the virus, indicating transmission via the fecal-oral route.
Interestingly, the infected pigs did not exhibit clinical symptoms, aligning with previous findings that rats also remain symptom-free. However, the detection of the virus in the cerebrospinal fluid of pigs expands the concern to potential neurological impacts. One human case involving rat HEV resulted in meningoencephalitis, a severe neurological condition.
“HEV is gaining importance for neurological disorders, and a lot of the research now points toward how neuropathology is caused by the hepatitis E virus,” added Yadav, who completed the study as a doctoral student at Ohio State and is currently a postdoctoral researcher at the Virginia-Maryland College of Veterinary Medicine at Virginia Tech. “And even though we have a small number of known human cases, a high percentage of them are immunosuppressed. That means transplant recipients in the United States could be at risk of infection by general HEV as well as rat HEV.”
Further research is anticipated to determine whether pork liver products contain rat HEV and to explore enhanced food safety measures to prevent transmission. This study sheds light on a critical new vector for rat HEV and underscores the need for vigilance in food safety and public health practices.