The Centre for Health Protection is investigating a fatal Japanese encephalitis case involving a 29-year-old foreign domestic helper living in Kau Wa Keng San Tsuen in Kwai Chung.

The woman developed neurological symptoms on May 29 and was admitted to Princess Margaret Hospital on June 2, but her condition deteriorated and she died on June 7. Serology tests on her blood confirmed Japanese encephalitis. This is the first case reported this year.

The woman had no recent travel history, and the case has been classified a local one. Her household contacts do not have any neurological symptoms. Their residence has been inspected and a survey is being conducted in their neighbourhood for active case finding and serological tests.

Prompt pest control has been conducted by the Food & Environmental Hygiene Department, which has been conducting weekly anti-mosquito work around piggeries since last summer. Larvicides have been applied to control mosquito breeding.

The centre has set up a telephone hotline (2575 1848) for enquiries. People who live around Kau Wa Keng San Tsuen, including Ha Kwai Chung, Lai King, Mei Foo and Lai Chi Kok, can call the hotline if they have a high fever, severe headache, vomiting, drowsiness, a seizure, or fear of light. Appropriate action for symptomatic individuals will be arranged. The hotline will be open until 9pm today and during office hours in the following days.

From 1992 to 2003, there have been six sporadic cases reported in Hong Kong, including a local case in 1996 and last year, and imported cases in 1997, 2001 and 2002.

Prevention tips

Japanese encephalitis is transmitted by Culicine mosquitoes living mainly in rural areas, which breed in waterlogged fields and marshes. Person-to-person transmission does not occur. The incidence of the illness in Hong Kong is low, however, people are reminded to take measures to prevent mosquito breeding by removing stagnant water.

They are also advised to take the following precautionary measures both in Hong Kong and when visiting areas with mosquito-transmitted diseases:

* wear long-sleeved clothes and trousers;

* use insect repellent over exposed parts of the body when outdoors; and,

* use mosquito screens or nets when the room is not air-conditioned.

Travellers who fall sick after returning from endemic areas should consult doctors promptly and give details of their travel history.

2 viral encephalitis cases reported, 1 fatal

The centre has received two other notifications from Princess Margaret Hospital of viral encephalitis, one of which was fatal. One of the patients was a 26-year-old foreign domestic helper who died on June 1. Another patient is a 24-year-old local woman who is now in critical condition. Both patients tested negative for Japanese encephalitis.

Viral encephalitis is caused by different viruses and it occurs around the world. In Hong Kong, the number of patients discharged from Hospital Authority hospitals per year during 2000-2003 ranged between 170 and 260. This year, there have been 70 cases.

The centre and the authority are setting up an alert system to monitor the occurrence of viral encephalitis cases in the coming weeks. Under the system, both public and private hospitals will report viral encephalitis cases for further investigation.

A set of Frequently Asked Questions on the surveillance of encephalitis cases and a revised Fact Sheet on Prevention & Management of Japanese Encephalitis in Hospitals will be issued to all public hospitals to facilitate clinical diagnosis and treatment of patients, and remind healthcare workers on the required infection control measures.

Details of preventive measures against Japanese encephalitis, viral encephalitis and other travel health advice are available from the centre's website and the Department of Health's travel health website.