In May, reports emerged in the British press about a “Brexit” virus, which turned out to be a new strain of hepatitis E linked to hog farms in France, Holland, Germany and Denmark.

Cases of hepatitis E have surged in Britain. According to provisional data from January -March 2017, Public Health England received 218 reports of severe Hepatitis E infections. In 2016, the agency had 1,244 cases.

The National Pig Association in the UK said in a statement that Public Health England research found that a subgroup of hepatitis E causing the majority of human infection in the United Kingdom is not the same as a subgroup found in UK pigs.

“The NPA agrees with the conclusion of the researchers that if people in this country have contracted hepatitis E virus from eating pork, it is likely to have come from imported pork, rather than British pork,” NPA said, adding that more research and surveillance is needed to determine “the true cause of the rise in hepatitis E cases in the UK.”

“NPA recommends that consumers follow the advice from the Food Standards Agency that pork and sausages should be cooked thoroughly until steaming hot throughout, with no pink or red in the center, to greatly reduce the risk of infection,” the organization said.

Consumers are advised to cook meat products thoroughly, avoid eating raw or undercooked shellfish and meat, and practice consistent, thorough handwashing before preparing, serving and eating food.

Hepatitis E is an illness of the liver caused by a virus that can infect people and animals. In rare cases, it can be fatal, especially in pregnant women. The virus can result in chronic inflammation of the liver in individuals with weakened immune systems.

Symptoms include yellowing of the skin and eyes, or jaundice; darkening of the urine and pale stools. Other symptoms can sometimes include fatigue, abdominal pain, fever and nausea.