Press Release

CHP investigating a confirmed case of Japanese encephalitis

June 10, 2004

The Centre for Health Protection (CHP) of the Department of Health is investigating a local case of Japanese encephalitis (JE) involving a 29-year-old female foreign domestic helper living in Kau Wa Keng San Tsuen in Kwai Chung.

The woman had onset of neurological symptoms on May 29. She was admitted to Princess Margaret Hospital on June 2 but her condition deteriorated and she passed away on June 7. Serology tests on her blood samples yielded positive result for JE.

This is the first JE case reported this year. CHP's investigations revealed that the patient had no recent travel history before the onset of illness. Therefore, the case has been classified as a local one.

The household contacts of the patient were visited by CHP's medical staff and were put under medical surveillance. They did not have any neurological symptom of JE. Their residence in Kau Wa Keng San Tsuen was also inspected.

Meanwhile, the CHP is conducting a survey among the neighbourhood of the patient's residence for active case finding and serological tests.

A CHP spokesman today (June 10) said: "JE is transmitted by the bite of infective Culicine mosquitoes. Person-to-person transmission does not occur."

"The incidence of JE in Hong Kong is low. Nonetheless, the CHP is conducting investigations to search for further possible cases," he added.

Prompt pest controls have been carried out by the Food and Environmental Hygiene Department (FEHD).

The FEDH has been conducting anti-mosquito actions around piggeries on a weekly basis since last summer. Larvicides have been applied to control mosquito breeding.

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

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

Japanese encephalitis is transmitted by Culicine mosquitoes living mainly in rural areas. The mosquitoes breed in water-logged fields and marshes. The public is 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 in 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 travel history.

The CHP spokesman said the CHP had received two other notifications from the Princess Margaret Hospital of viral encephalitis, one of which was fatal. One of the patients is a 26-year-old female foreign domestic helper who died on June 1. Another patient is a 24-year-old local woman who is now in critical condition in the hospital. Laboratory results of both patients were negative for JE.

Viral encephalitis is caused by different viruses and it occurs around the world. In Hong Kong, the number of patients discharged from Hospital Authority's hospitals per year during 1998-2003 ranged between 170 and 260. So far this year, the number of viral encephalitis is about 70, which does not appear to be increasing.

The CHP and Hospital Authority are setting up an alert system to monitor the occurrence of viral encephalitis cases in the coming three weeks. Under this system, both public and private hospitals will report to the CHP about viral encephalitis cases for further investigations.

A set of Frequently Asked Questions (FAQs) on the surveillance of encephalitis cases and a revised Fact Sheet on Prevention and Management of Japanese Encephalitis in Hospitals will be issued by HA Central Committee on Infectious Diseases to all public hospitals to facilitate clinical diagnosis and treatment of patients, as well as reminding health care workers on the required infection control measures.

Details of the preventive measures against JE, viral encephalitis and other travel health advice are available from CHP's website (This link will open in a new windowhttp://www.chp.gov.hk) and DH's website on travel health (This link will open in a new windowhttp://www.info.gov.hk/trhealth).