A research study led by the Singapore General Hospital (SGH) has shown that the incidence of hepatitis E (HEV) among Singapore residents had increased from 1.7 cases per 100,000 residents in 2012 to 4.1 cases per 100,000 residents in 2016 (i.e. about 1 in 25,000 residents). The HEV infected individuals tend to be Chinese, male and aged 55 years and above. HEV subtyping was done on 59 of 449 patient blood samples.
Seventy-five per cent (44/59) of the subtyped samples show that the strain belongs to HEV genotype 3a, which is the same subtype detected in three raw pork liver samples. The study findings were published in the peer-reviewed medical journal Zoonoses Public Health in July 2019.
What is Hepatitis E?
Hepatitis E is a virus that infects the liver. Most patients show no symptoms but if they do, the symptoms include fever, feeling very tired (lethargy), nausea and jaundice. The infection goes away on its own after a few weeks, and it usually does not lead to long-term illness or liver damage. However, it can be dangerous for pregnant women or anyone with weak immune systems like transplant patients, or people with pre-existing chronic liver disease.
HEV can be acquired by ingesting faecally contaminated water or eating raw or undercooked products from infected animals. Worldwide, HEV foodborne infection is generally associated with the consumption of pork meat/offal, game meat, and shellfish.
Animals such as pigs, wild boars and deer are zoonotic reservoirs of HEV. In Europe, the consumption of raw or undercooked pork or pork products is the most common cause of hepatitis E infection. Closer to home, Hong Kong’s Centre for Food Safety issued a report in December 2010 about eating undercooked pig livers for the same reason.
Cooking your food thoroughly
“Although we could not ascertain if pig liver is the main contributor of HEV cases in Singapore, we observed that pig liver can be found in many local dishes. As most people like it a little undercooked for its texture, this may put them at risk of hepatitis E infection. The safest way of consuming food, including pork, is to cook it thoroughly,” said Dr Chan Kwai Peng, senior author of the study and Senior Consultant, Department of Microbiology, SGH.