Thursday, December 30, 2010

Hepatitis E cases on the rise in Hong Kong

Fri, Dec 31, 2010
China Daily/Asia News Network
By Guo Jiaxue

HONG KONG - Doctors' advice: Cook food more thoroughly, particularly pig livers

The Centre for Food Safety (CFS) warned of rise in cases of Hepatitis E in Hong Kong and appealed to citizens to cook food more thoroughly, particularly pig livers.

"The number of reported cases of Hepatitis E has been climbing since 1998. It's more than 100 in 2010, the highest ever in the city," said Ho Yuk-yin, doctor and consultant on Risk Assessment and Communication at the CFS. The number was less than 10 in 1999 and less than 40 in 2006, according to the Centre for Health Protection (CHP).

But the CFS is yet to know why. "It's not just in Hong Kong, but many other areas also, where more locally infected cases have been reported," Ho said, "a lot of scientists are still exploring the reasons."

Hepatitis E viruses are mainly transmitted though contaminated water or food. Symptoms include fever, malaise, anorexia, nausea, dark urine and jaundice. The disease is mild and spontaneously resolves in two weeks, leaving no sequela.

But it could be dangerous for pregnant women and patients with pre-existing chronic liver diseases. The case-fatality rate can reach 70 percent among the latter.

The human cases of Hepatitis E are rare in developed countries. Most of the afflicted are said to have visited endemic-prone developing countries. Yet an increase in sporadic cases has been reported even from those who haven't traveled abroad in recent years, Ho added.

An analysis of 51 human cases in Hong Kong by the CHP in 2008 found 65 of them had never gone to any endemic-prone areas.

The CFS believes that the semi-cooked pork livers could be a major source of Hepatitis E in Hong Kong.

To study a possible relationship between pork livers and Hepatitis E virus, the center collected 100 fresh pig livers from slaughterhouse in 2009, and found none of the 6-month pigs was infected with Hepatitis E virus, while 31 percent of 4-month pigs were infected.

The CFS compared the virus detected from the 48 human cases reported during the first seven months in 2009 with those from pigs and found seven partial matches. "The finding suggests that undercooked pork livers could be a source of human Hepatitis E cases," Ho said.

"It's important for all to cook food more thoroughly to lower the risk," Ho said, noting some people like to eat half-cooked pork livers. "Particularly these people must be more alert. Viruses are more resistant to heat than bacteria," Ho explained.

Ho advised all to boil sliced pig liver at 100 centigrade or stir-fry for at least three to five minutes. For shellfish, either boiling for additional three to five minutes after their shells open, or heating to an internal temperature to 90 centigrade for 90 seconds, is necessary.

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