The Food and Environmental Hygiene Department (FEHD) today (May 20) announced that the monthly gravidtrap index for Aedes albopictus mosquitoes in April was 4.2 per cent. The index in April remained at the lowest Level 1, indicating that the distribution of Aedes albopictus mosquitoes in the areas surveyed was not extensive.
In April, among the 64 survey areas, there was only one area (Hung Hom) with the area gravidtrap index exceeding the alert level of 20 per cent. Positive gravidtraps in the district concerned 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 April was 1.2, which represented that an average of 1.2 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, "As summer is approaching, the FEHD reminds members of the public to carry out early effective prevention and control measures against mosquitoes as mosquitoes breed quickly in the hot and rainy weather. The Government has long been concerned about mosquito infestation. 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. Under the concerted efforts and collaboration of various parties, the index in April remained at a low level. 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 levelled to reduce the chance of mosquito breeding."
In view of a local dengue fever (DF) case earlier, 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 he 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 will run until 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. 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 so as 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. The dengue activity in neighbouring areas has remained high and Hong Kong has recorded 22 imported DF cases and one local DF case so far this year. Members of the public should stay vigilant and continue to carry out effective mosquito prevention and control measures.