Monthly gravidtrap index for Aedes albopictus mosquitoes of January remains at lowest level


     The Food and Environmental Hygiene Department (FEHD) today (February 14) announced that the monthly gravidtrap index for Aedes albopictus mosquitoes in January dropped further to 0.3 per cent from 0.8 per cent in December last year. The index in January remained at the lowest Level 1, indicating that the distribution of Aedes albopictus mosquitoes in the areas surveyed was not extensive.

     All the 64 survey areas were recorded with a gravidtrap index lower than the alert level of 20 per cent. Moreover, the monthly density index for Aedes albopictus in January was 1.1, which represented that an average of 1.1 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

     A spokesman for the FEHD said, “The Government is very concerned about mosquito infestation. The FEHD has continued to intensify mosquito prevention and control work with relevant government departments in areas under their purview, including eliminating mosquito breeding places, applying larvicides, conducting fogging operations to eradicate adult mosquitoes, and placing mosquito trapping devices at suitable locations. The FEHD has also conducted site inspections with relevant departments, and provided them with professional advice and technical support to assist them in formulating and implementing effective anti-mosquito measures swiftly. At the same time, the FEHD has strengthened publicity and education. Under the concerted efforts and collaboration of various parties, the index in January dropped further. Although the index remains at a low level, the warm and humid weather of spring is favourable for mosquito breeding. The FEHD will continue to monitor the mosquito infestation in all districts, and will conduct prompt and effective mosquito prevention and control work. At the same time, members of the public are advised to continue the routine mosquito prevention and control work, especially the repair and maintenance of structures. Cracks and dents which may accumulate water and become potential breeding grounds should be filled and leveled so as to reduce the chance of mosquito breeding when the rainy season approaches.”

     The FEHD will conduct a three-phase Anti-mosquito Campaign this year. The first phase of the territory-wide campaign will be launched on February 19 and will run until March 17. During the period, the district offices of the FEHD will target areas that have drawn particular concern, such as public markets, cooked food centres and hawker bazaars, single-block buildings, streets and back lanes, common parts of buildings, village houses, construction sites, vacant sites and road works sites, to remove accumulated water and carry out 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). 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 eight 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.