Monthly gravidtrap index for Aedes albopictus mosquitoes in December 2024 remains at lowest level

     The Food and Environmental Hygiene Department (FEHD) today (January 15) announced that the monthly gravidtrap index for Aedes albopictus mosquitoes in December 2024 was 0.7 per cent, which remained at the lowest Level 1, indicating that the distribution of Aedes albopictus mosquitoes in the areas surveyed was not extensive.

     In December last year, all 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 December last year was 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 website at www.fehd.gov.hk.

     A spokesman for the FEHD said, "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 provided government departments with professional advice and technical support to assist them in swiftly formulating and implementing effective anti-mosquito measures while strengthening publicity and education at the same time. Under the concerted efforts and collaboration of various parties, the index in December last year remained at the lowest level. 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 started its territory-wide year-end clean-up campaign on January 6, which will last for 21 days. During the campaign, mosquito prevention and control work will be enhanced, including carrying out inspections, removing stagnant water, applying insecticide and disposing of abandoned water containers weekly to prevent mosquito breeding, and trimming of grass to discourage resting of adult mosquitoes on the site. 

     The FEHD appeals to members of the public to continue to stay alert and 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. In 2024, the World Health Organization recorded over 13 million DF cases, which was a record number. Hong Kong recorded 156 imported DF cases and five local DF cases in 2024. Members of the public should continue to carry out effective mosquito prevention and control measures proactively.