Despite the continued fall of ovitrap indices, the public should stay vigilant against Dengue fever and continue to take necessary prevention and control measures, the Food & Environmental Hygiene Department says.

The department said the monthly ovitrap index, which reflects the prevalence of Aedes albopictus, a vector for Dengue fever, stood at zero last month, compared with 0.1% in January last year. The index for port areas stood at 0.1%, the same as December.

Revealing the figures today, the department's Consultant Dr Ho Yuk-yin said the low figures reflect the seasonable variation and there is absolutely no room for complacency.

Spring rains could trigger eggs to hatch

"The figures may take a quick turn when mosquito eggs start to hatch with the spring rain. We should spare no effort in implementing anti-mosquito measures," he said.

Keeping our homes and surroundings clean is the most effective way to prevent mosquito breeding, Dr Ho said.

People should pay particular attention to small containers such as vases, saucers, trays and damp surfaces in depressions. They are all favourable places for mosquitoes to lay eggs.

They should also change water for plants, which they use to decorate their homes during the Lunar New Year, at least once a week.

Take preventive measures when travelling abroad

Dr Ho also reminded people planning to travel abroad during the holidays to take preventive measures when visiting areas where Dengue fever was endemic.

They should:

* wear light-coloured, long-sleeved clothes and long trousers;

* use insect repellent on exposed parts of the body; and

* use mosquito screens or nets when staying in rooms that are not air-conditioned.

As regards the department's year-long territory-wide Japanese encephalitis vectors survey, Dr Ho said specimens of adult Culex tritaeniorhynchus, commonly found in Hong Kong, were found in Yuen Long, North District, Lantau Island, Central & Western District and Shatin.

The virus was not found in the specimens collected, he said. Despite that, the department has strengthened its mosquito control action in the areas concerned and provided technical support to other departments and organisations involved in operations against mosquito breeding, he added.

The ovitrap indices and information on anti-mosquito measures are available on the department's website and its hotline, 2868 0000.

Information and health advice on Dengue fever and Japanese encephalitis are available on the Centre for Health Protection's website, or the hotline of the Department of Health's Central Health Education Unit, 2833 0111.