Announcement on epidemiology and prevention of Hepatitis E in Hong Kong

The Centre for Food Safety (CFS) today (December 30) announced the epidemiology of Hepatitis E in Hong Kong, reported that fresh pig liver may be one of the sources in the spread of food-borne Hepatitis E virus (HEV) in Hong Kong, and advised people on preventive measures.

In light of a rising trend in local human Hepatitis E cases in recent years, the CFS obtained 100 fresh liver samples from pigs slaughtered in Sheung Shui Slaughterhouse from mid-January to May 2009. Among those samples, none of the 49 liver samples from porker pigs (around six months old) was found to be positive for HEV, while 16 out of 51 liver samples from roaster pigs (roughly four months old) were found to be positive. The positive rate for roaster pigs was 31%. Some isolates from roaster pigs and human cases were also found to have the same partial sequence.

Speaking at a press conference today, CFS' Consultant (Community Medicine) (Risk Assessment and Communication), Dr Ho Yuk-yin, said, "The results of the study show that the pig may be one of the sources of local human Hepatitis E cases. But there are other potential sources, such as contaminated water and food like raw or undercooked shellfish.

"Those local cases were all sporadic. As the incubation period of HEV varies from two to nine weeks, it is difficult to determine the exact source of infection for individual cases.

"The CFS will take note of the HEV situation in humans and animals in order to have an overview of the epidemiology of Hepatitis E," Dr Ho said.

Co-hosting the press conference was CFS' Scientific Officer (Microbiology), Dr Chong Tsz-kit. He said, "People infected with HEV may have symptoms such as fever, malaise, anorexia, nausea, abdominal pain, jaundice and tea-coloured urine. It is usually a mild disease and resolves in two weeks. However, there may be severe complications in high risk groups, such as pregnant women, patients with chronic liver diseases and the elderly. No commercial vaccine for Hepatitis E is available at present."

Dr Chong said a number of overseas studies reported that HEV was more commonly detected in pigs, especially those aged four months or younger, and they may be a potential source of human Hepatitis E cases. The CFS' study results echo those conducted overseas.

On food safety, Dr Chong said, "The public and the trade should cook pork and offal thoroughly, especially when cooking in a hotpot or with congee. Sliced pig liver should be boiled at 100 degrees Celsius or stir-fried for at least three to five minutes depending on thickness and quantity.

"For shellfish, people should heat it to an internal temperature of 90 degrees Celsius for at least 90 seconds. Shellfish should be boiled at 100 degrees Celsius until their shells open and afterwards for another three to five more minutes. Consumers should use separate utensils for handling raw and cooked food, especially for a hotpot."

Dr Chong also reminded people to practise good personal and food hygiene. They should wash hands thoroughly under running tap water with soap for 20 seconds before handling food, during food preparation, after handling raw meat or offal, as well as before meals. Travellers should avoid drinking water or ice of unknown purity or eating uncooked shellfish, fruits or vegetables that have been peeled or prepared in advance for sale.

Details of the study are available on the CFS website

Ends/Thursday, December 30, 2010
Issued at HKT 16:26