Public urged to keep up anti-mosquito efforts
The Food and Environmental Hygiene Department (FEHD) announced today (March 15) that the monthly territory-wide ovitrap index for Aedes albopictus for February remained at 0.1 per cent, same as January's index, indicating that the infestation of Aedes albopictus in the areas surveyed was not extensive. Nevertheless, the FEHD reminded the public to carry out early effective measures against mosquitoes as Hong Kong is expecting a warmer and wetter spring this year which is favourable for large-scale mosquito breeding.
"Aedes albopictus is a kind of mosquito that can transmit dengue fever (DF) and Zika virus. Although the ovitrap index for Aedes albopictus remained at a low level in the past few months, in view of the 29 local DF cases recorded in Hong Kong last year and the high prevalence of DF in neighbouring areas, and that Hong Kong's warm and humid weather of spring is conducive to the hatching of mosquito eggs in a short period of time, resulting in a large amount of adult mosquitoes, the community must remain vigilant and take effective mosquito control measures early," an FEHD spokesman said.
Among the 57 areas surveyed last month, positive ovitrap indices were recorded in three areas, namely Happy Valley (1.8 per cent), Wo Che (1 per cent) and Ma On Shan (0.8 per cent). As for the port areas, the monthly ovitrap index for Aedes albopictus for February remained at zero.
"The FEHD and relevant government departments will continue to intensify their mosquito prevention and control work covering areas under their purview and strengthen publicity and education campaigns. The FEHD is conducting a three-phase Anti-mosquito Campaign this year. The first phase of the territory-wide campaign, lasting for four weeks, started on February 25 and will end on March 22. During the period, mosquito prevention and control work has been enhanced by the FEHD and relevant government departments. The district offices of the FEHD have targeted areas which 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, and stepped up publicity at those places as well as mosquito prevention and control work at relevant public places. The FEHD will, after the first and second phases of the campaign, conduct special territory-wide thematic mosquito prevention and control special operations so as to enhance the effectiveness of the campaign," the spokesman said.
The department's Pest Control Inspection Teams have also stepped up inspection of construction sites and enforcement action against mosquito breeding. This year (as at March 10), the FEHD has instituted 12 prosecutions for mosquito breeding found in relevant premises under the Public Health and Municipal Services Ordinance (Cap 132), mainly involving construction sites.
In order to keep the public abreast of the latest situation of mosquito infestation and assist them to take timely mosquito prevention and control measures, the FEHD is releasing additional results of the Area Ovitrap Index (AOI) for Aedes albopictus at two more stages every month, before the announcement of the monthly AOI and the monthly ovitrap index for Aedes albopictus. The FEHD will follow the established practice of notifying relevant government departments of the aforementioned indices so that they can carry out targeted mosquito prevention and control work promptly to strengthen the anti-mosquito efforts.
The spokesman added that as Aedes albopictus breeds in small water bodies, members of the public should carry out effective mosquito prevention and control measures, including inspecting their homes and surroundings to remove potential breeding grounds, changing all the water in vases and scrubbing the inner surface as well as removing the 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. He also advised the public and estate management bodies to keep drains free of blockage and level all defective ground surfaces to prevent 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.
In addition, rural areas and the vicinity of shrubby areas are the natural habitats for mosquitoes, other insects and animals. Members of the public living in rural areas may install mosquito screens on windows and doors if necessary. Those staying in the natural environment should follow appropriate personal protective measures against mosquitoes, such as avoiding staying in the vicinity of shrubby areas for a long time, wearing light-coloured long-sleeved clothes and trousers and applying DEET-containing insect repellent. Members of the public are reminded to make reports to the government departments via 1823 if mosquito problems are detected.
The spokesman reiterated that effective mosquito control requires the sustained effort of all parties concerned. The community must work together with the Government to carry out effective mosquito control measures.
The ovitrap index is divided into four levels, reflecting the infestation level of Aedes albopictus. Level 1 (< 5 per cent) indicates that infestation of the mosquito is not extensive in the area surveyed. Level 2 (5 per cent – < 20 per cent) indicates that infestation of the mosquito is slightly more extensive in the area surveyed. Level 3 (20 per cent – < 40 per cent) indicates that infestation of the mosquito exceeds one-fifth of the area surveyed. Level 4 (>/= 40 per cent) indicates that almost half of the surveyed area is infested with the mosquito. The Government will step up the scale of anti-mosquito operations according to the level of infestation as well as reports from front-line staff and the public.
As Aedes albopictus can transmit DF and Zika virus, ovitraps are set in 57 areas in Hong Kong for monitoring the breeding of Aedes albopictus, which is only one of the mosquito species commonly found in Hong Kong and is active only in the daytime. The index only indicates the extensiveness in distribution of Aedes albopictus within the 57 areas but does not capture its activity outside these areas and it also does not measure the prevalence of other kinds of mosquitoes.
The ovitrap indices for Aedes albopictus in different areas and information on mosquito prevention and control measures are available on the department website at www.fehd.gov.hk.