MARY ANN BENITEZ

Those worried about catching dengue fever from mosquitoes can apparently rest easier, thanks to the onset of drier weather and preparations being made by the government for next year's wet season.

A regular "mosquito index" will be published to warn people of the rising risk of catching dengue fever as conditions change.

According to a steering committee overseeing the government's response to the disease, the new Average Ovitrap Index is part of a multi-pronged approach to fighting dengue fever. Since July 20 people have contracted the mosquito-borne disease in Hong Kong.

In addition, the current spraying campaign will be extended through the winter and spring.

Carrie Yau Tsang Ka-lai, head of the Health, Welfare and Food Bureau and chairwoman of the steering committee, said the mosquito-breeding index would measure the percentage of special traps laid by the government found to have larvae in them.

"This will help government departments take timely action and enable members of the public to learn about the risk of mosquito bites at different times of the year," Mrs Yau said.

The ovitraps are small cup-like devices for detecting the larval breeding rate of mosquitoes. They are filled with water to attract female Aedes mosquitoes - the species that carries dengue fever - to lay eggs.

But Friends of the Earth director Mei Ng Fong Siu-mei warned that overspraying could kill not only the mosquitoes but their predators too, putting Hong Kong's ecosystem and food chain at risk.

maryann.benitez@scmp.com

Tuesday, October 1, 2002
Fever facts

• Dengue fever is a viral infection transmitted to humans through the bites of infected Aedes mosquitoes. The mosquitoes generally acquire the virus while feeding on the blood of an infected person. Infected female mosquitoes may also transmit the virus to their offspring.

  Symptoms:

• High fever, severe headache, pain behind the eyes, muscle and joint pains and rash. Dengue hemorrhagic fever is a severe, potentially fatal strain. There is neither a specific treatment for dengue fever, nor any vaccine.

  Prevention:

  World Health Organisation guidelines - The only method is to combat the infected mosquitoes by using insecticide and eliminating potential breeding grounds, such as covering open containers to prevent stagnant water collecting and prevent access by egg-laying mosquitoes.

• Hong Kong's guidelines - Put used cans and bottles into dustbins; change water for plants at least once a week, leaving no water in the saucers underneath flower pots; cover all water containers, wells and water storage tanks; keep all drains clear. Wear long-sleeved clothes and long trousers; use insect repellent, mosquito screens and nets.