Public urged to strengthen anti-mosquito efforts

     The Food and Environmental Hygiene Department (FEHD) today (June 24) announced that the monthly gravidtrap index for Aedes albopictus mosquitoes in May was 13 per cent, at Level 2, indicating that the distribution of Aedes albopictus mosquitoes in the areas surveyed was fairly extensive. Relevant government departments have stepped up mosquito prevention and control actions. 

     In May, among the 64 survey areas, the area gravidtrap index in 10 areas exceeded the alert level of 20 per cent. The gravidtraps were mostly located in the vicinity of private residential areas, public housing estates, 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. 

     Moreover, the monthly density index for Aedes albopictus in May 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, "There is a significant relationship between local mosquito infestation and seasonal changes. The gravidtrap indices in various survey areas would be relatively higher during hot and rainy spring and summer months (i.e. from May to September) as mosquitoes breed quickly. Members of the public are reminded 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 levelled to reduce the chance of mosquito breeding.

     "The Government is concerned about the mosquito infestation in May. The increase in the monthly gravidtrap index for Aedes albopictus for May might be related to the continuously hot and rainy days in the month. The interdepartmental Pest Control Steering Committee held a meeting on June 3 to review the latest situation of mosquito infestation and the anti-mosquito work taken by departments. The FEHD has continued to intensify the 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. The FEHD will continue to monitor the mosquito infestation in all districts, and will conduct prompt and effective mosquito prevention and control work," the spokesman continued.

     In view of the second local dengue fever (DF) case reported recently, the FEHD has immediately conducted surveys of mosquito infestation and has carried out additional targeted mosquito prevention and control work (including conducting fogging operations, applying larvicides and placing mosquito trapping devices) in areas within a 250-metre radius of the residence and workplace of the patient, as well as places the patient had visited during the incubation and infectious period. The FEHD has also stepped up inspections and taken enforcement actions where necessary.

     The FEHD will conduct a three-phase Anti-mosquito Campaign this year. The second phase of the territory-wide campaign was launched on April 15 and ended on June 16. 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. After the second phase of the campaign, the FEHD has conducted territory-wide thematic special operations on mosquito prevention and control, such as strengthening mosquito control at individual construction sites, for three weeks starting from June 24. To further enhance the effectiveness of mosquito control, the FEHD and relevant government departments have carried out the second phase of the All-out Anti-mosquito Operations since May 2 to focus on eliminating potential mosquito breeding places, and called on property managements to arrange necessary repairs to their premises to minimise mosquito breeding places. Furthermore, intense adult control has been conducted by means of regular ultra-low volume fogging operations after the onset of the rainy season.

     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 DF. DF is commonly found in tropical and subtropical regions of the world, and has become endemic in many countries in Southeast Asia. Based on the latest surveillance data from the Centre for Health Protection of the Department of Health, there has been an increase in DF cases in some places in Asia thus far, compared with the corresponding period of last year. The Americas (including Brazil, Argentina and Peru) have even recorded over 8 million cases, which is a record number, since the beginning of 2024. The dengue activity in neighbouring areas is high and Hong Kong has recorded 28 imported DF cases and two local DF cases so far this year. Members of the public should carry out effective mosquito prevention and control measures proactively.