Study detects traces of hepatitis E in Quebec pork liver products

A group of pigs at a farm in Quebec. (Daniel J. Rowe/CTV News)

The first study of its kind in Quebec has detected traces of the hepatitis E virus in pork liver. Researchers at Laval University detected the virus' ribonucleic acid (RNA) in raw pork liver and liver pâtés obtained in Quebec stores and slaughterhouses.

"We suspected that the virus was circulating in these animals, especially in pork, which is one of the reservoirs of this virus. But we really wanted to confirm whether this was the same thing as what was happening elsewhere [in the world]," said study leader Julien Jean, a food science professor and researcher at the university.

"We wanted to get a better picture of what was going on. So, we weren't totally surprised to find the virus RNA."

In the summer of 2022, researchers purchased 83 pâtés with pork liver listed as one of the main ingredients from Quebec grocery stores.

They also obtained 79 samples of raw pork liver from slaughterhouses across the province.

Twenty-nine per cent of pâtés and four per cent of raw liver samples tested positive for virus RNA. The discrepancy may be because different pork livers are mixed together to make one paté.

Researchers don't yet know if the RNA belongs to active viruses or if it was freed from viruses destroyed during thermal treatment used to prepare the patés.

"We don't currently have reliable-enough methods to really determine whether the infectious virus is inside the product," said Jean. "When we detect the RNA, we don't doubt that the virus was there at some point, but that doesn't guarantee [...] that the virus can actually cause disease."

Her team's next steps involve examining whether the preparation methods used in paté manufacturing are enough to neutralize the virus.

Less known than its cousins A, B, C, and D, hepatitis E causes inflammation of the liver, according to the World Health Organization (WHO).

The virus is transmitted via the fecal-oral route, mainly through contaminated water.

Some 20 million people are believed to be infected with the virus every year, main in east and south Asia.

The symptoms of hepatitis E -- like fever, jaundice, reduced appetite and vomiting -- can be impossible to distinguish from those caused by other forms of hepatitis.

No case of hepatitis E in Quebec has been connected to pork consumption. These foods therefore appear to pose little risk to individuals' health.

But, in rare cases, the WHO warns that acute hepatitis E can be severe and even fatal.

Pregnant women with hepatitis are at an increased risk of acute liver failure, fetal loss and death, especially in their second and third trimesters.

Given these facts, consuming pork liver products may represent an unnecessary risk for some, Jean says.

"It remains a potential risk that needs to be better evaluated to ensure that pregnant women who wish to consume these products do not find themselves in a situation that could lead to fairly serious complications," she said.

The study was published in the journal Frontiers in Sustainable Food Systems.

This report by The Canadian Press was first published in French on July 13, 2023.