Thirteen out of 17 areas surveyed have recorded positive area ovitrap indices, with two over 10%, the Food & Environmental Hygiene Department says. They were Diamond Hill (19.1%) and Cheung Sha Wan (13.5%). Indices for the other 11 areas ranged from 1.8% to 9.8%.

The department's Community Medicine Consultant Dr Ho Yuk-yin said while results for the remaining 21 areas are pending, people should stay alert to mosquito breeding. Though none of the area ovitrap indices entered the alert zone of 20%, the indices rebounded in some of the surveyed areas and may surge sharply in a short period of time.

"Dengue cases are being reported in our neighbouring areas. There have been 24 imported cases of Dengue fever reported so far this year. Guangdong, in particular, has seen a drastic surge in the number of Dengue fever cases recently," Dr Ho said.

"We are highly vulnerable to Dengue fever, given the intense population movement between Hong Kong and the neighbouring areas."

Enhanced control

Mosquito prevention and control has been enhanced in various districts, especially the port areas. Cross-boundary transport companies have been reminded to take anti-mosquito measures.

Travellers should wear light-coloured, long-sleeved clothes and long trousers, and use insect repellent when visiting areas infected by mosquito-transmitted diseases. They are urged to use mosquito screens or nets when staying in rooms that are not air-conditioned.

Travellers coming back from these places should seek medical advice as soon as possible if they have symptoms including high fever, severe headache or muscle and joint pain. They should tell the doctor of their travel history.

The ovitrap indices and information on anti-mosquito measures are available here or through the department's hotline, 2868 0000. More details and health advice on Dengue fever can be found here, or call the Department of Health's hotline, 2833 0111.