The Food & Environmental Hygiene Department urges people to step up anti-mosquito efforts as the monthly ovitrap index rose from 4.9% in April to 10.3% in May. The index for port areas also rose from 0.1% to 0.4%.

The ovitrap indices reflect the prevalence of Aedes albopictus, a mosquito vector for Dengue fever transmission. Indices for 16 areas found that two - Tsing Yi (36.5%) and Fanling (26%) - had their readings fall into the alert zone of 20% to 40%. Indices for the remaining 22 areas range from 2.3% to 15.5%.

The department's Consultant Dr Ho Yuk-yin said the ovitrap indices can increase further in the coming months. He appealed to the public to step up anti-mosquito measures promptly.

He also urged people to stay alert to the risk of Japanese encephalitis following confirmation of the virus in another batch of specimens of adult Culex tritaeniorhynchus. They were collected during vector surveys in Yuen Long following a suspected Japanese encephalitis case. Government departments have strengthened inspections and mounted special operations in the vicinity to clean up the environment and remove mosquito breeding places.

Prevention tips

People should:

* wear long-sleeved clothes and trousers when staying outdoors after dusk;

* use insect repellent on exposed parts of the body;

* use mosquito screens or nets when the room is not air-conditioned; and,

* ensure continuous water flow of water-logged fields by installing devices such as water pumps and gates, and removing stagnant water regularly.

For anti-mosquito information, visit the department's website or call 2868 0000.