October’s monthly gravidtrap index for Aedes albopictus drops further

     The Food and Environmental Hygiene Department (FEHD) today (November 29) announced that the monthly gravidtrap index for Aedes albopictus in October dropped further to 2.8 per cent from 5.3 per cent in September, which was at Level 1 at its lowest, indicating that distribution of Aedes albopictus in the areas surveyed was not extensive.

     Among the 64 survey areas, there was only one area (Yuen Long Town) with the area gravidtrap index (AGI) exceeding the alert level of 20 per cent. The gravidtraps in the district concerned were mostly located in the vicinity of private residential areas, schools, recreational and sports facilities and public places. The FEHD has collaborated with relevant government departments by taking immediate action to strengthen mosquito prevention and control work in the area concerned. The AGI in the district concerned in November has dropped significantly to a lower level at 8.5 per cent.

     Moreover, the monthly density index for Aedes albopictus in October remained at 1.3, which represented that an average of 1.3 Aedes albopictus adults were found in the Aedes-positive gravidtraps, indicating that the number of adult Aedes albopictus was not abundant in the survey areas. The gravidtrap and density indices for Aedes albopictus in different survey areas as well as information on mosquito prevention and control measures are available on the department's website at www.fehd.gov.hk.

     A spokesman for the FEHD said, "Under the concerted efforts and collaboration of various government departments, the index in October dropped further. The FEHD will continue to monitor the mosquito infestation in all districts, and will conduct prompt and effective mosquito prevention and control work."

     The FEHD appeals to members of the public to work together to carry out mosquito prevention and control measures early, including inspecting their homes and surroundings to remove potential breeding grounds, changing water in vases and scrubbing their inner surfaces, removing water in saucers under potted plants at least once a week, properly disposing of containers such as soft drink cans and lunch boxes, and drilling large holes in unused tyres. The FEHD also advises members of the public and estate management bodies to keep drains free of blockage and level all defective ground surfaces to prevent the accumulation of water. They should also scrub all drains and surface sewers with an alkaline detergent at least once a week to remove any mosquito eggs.

     Aedes albopictus is a kind of mosquito that can transmit dengue fever (DF) as well as Zika virus infection. DF is commonly found in tropical and subtropical regions of the world, and has become endemic in many countries in Southeast Asia. The dengue activity in neighbouring areas has remained high and Hong Kong has recorded 21 imported DF cases so far this year. Members of the public should stay vigilant and continue to carry out effective mosquito prevention and control measures.