The Centre for Health Protection is investigating a suspected case of Japanese encephalitis involving a five-year-old Lau Fau Shan boy. Laboratory tests are being performed to confirm the diagnosis and results are expected early next week.

As a precautionary measure, the Food & Environmental Hygiene and Agriculture, Fisheries & Conservation Departments are conducting vector surveys and mosquito control measures near the boy's residence in Sha Kong Tsuen. There are some pig farms within two kilometres of his home.

The boy, with no recent travel history, developed fever, runny nose, sore throat, vomiting and diarrhoea on October 16. He was admitted to Tuen Mun Hospital on October 19 and is in a stable condition.

No spread

Four households who have been in contact with the boy have been put under medical surveillance. They have no neurological symptoms so far. The boy's kindergarten has also been inspected and nobody has been found to have developed symptoms.

The illness is transmitted by Culicine mosquitoes living mainly in rural areas. The mosquitoes breed in waterlogged fields and marshes.

People are reminded to take measures to prevent mosquito breeding by removing stagnant water. And when in mosquito-prone areas, wear long sleeved clothes and trousers, use insect repellent, and mosquito screens or nets.

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