A senior health official yesterday said she was not optimistic about achieving a promise by the health minister to reduce the number of mosquitoes to below danger levels by next month. The remark by Carrie Yau Tsang Ka-lai, permanent secretary for health, welfare and food, came three days after her boss, Yeoh Eng-kiong, vowed to bring mosquito numbers down in all Hong Kong's 18 districts by next month. Speaking after the opening ceremony for a seminar on pest control at the Hong Kong International Trade and Exhibition Centre in Kowloon Bay, Mrs Yau said: 'We would like to bring down the ovitrap reading by stepping up mosquito control measures. However, I am not optimistic about it because we are unable to control the weather and there is a lot of vacant land and hillsides in Hong Kong.' Ho Yuk-yin, consultant for the Food and Environmental Hygiene Department, said departments should clear stagnant water in the areas under their management. Last month the ovitrap index reached a Hong Kong-wide average of 31.6 per cent, with 30 of the 38 monitoring stations exceeding the alert level. The highest level was 61.8 per cent in Tai Wai. The index is calculated by counting the Aedes albopictus mosquito eggs laid in special traps at various sites. The Observatory recorded 104.3mm of rainfall in March and 147.2mm in April. Rainfall in May totalled 194.4mm, against 249mm a year ago. Mrs Yau said the bureau had no plans to increase the penalty for anyone allowing stagnant water to accumulate. The penalty is a maximum fine of $25,000 and a daily fine of $450. At the seminar, organised by the Food and Environmental Hygiene Department, Harold Harlan, a pest control expert from the United States, warned against yellow fever and malaria, two of the most common mosquito-borne diseases. Dr Harlan said Aedes albopictus mosquitoes could transmit dengue fever and yellow fever. However, he said dengue fever was a bigger threat to Hong Kong. He said yellow fever was more common in Africa and there had been an effective vaccine for about 10 years. 'But there are no vaccines for dengue. Also, you probably have more people coming in and out of places where dengue fever has been transmitted,' he said.
