The Food and Environmental Hygiene Department (FEHD) announced today (November 19) that the monthly territory-wide ovitrap index for Aedes albopictus dropped further, from 6 per cent in September to 2.2 per cent in October, indicating that the infestation of Aedes albopictus in the areas surveyed was not extensive. The FEHD reminded the public to keep on implementing effective measures against mosquitoes even winter is approaching.
"Aedes albopictus is a kind of mosquito that can transmit dengue fever (DF) and Zika virus. In view of the 29 local DF cases recorded in Hong Kong so far this year, and that DF is also highly prevalent in neighbouring areas, as well as the relatively high temperature of autumn and winter in Hong Kong which is favourable for mosquito breeding, the public must remain vigilant and work with the Government to continue to carry out effective mosquito prevention and control measures," an FEHD spokesman said.
Among the 57 areas surveyed last month, positive ovitrap indices were recorded in 38 areas, ranging from 0.9 per cent to 8.8 per cent, with the highest in Ma On Shan. As for the port areas, the monthly ovitrap index for Aedes albopictus for October fell to 0.2 per cent from 1.4 per cent in September.
"The FEHD and relevant government departments will continue to intensify their mosquito preventive and control work covering areas under their purview and strengthen publicity and education campaigns. The FEHD has launched a special territory-wide thematic mosquito prevention and control operation on October 29, which will continue in the winter season and last till January 11, 2019. Relevant departments have also participated in the operation. The district offices of the FEHD will target areas which have drawn particular concern, such as single-block buildings, village houses, construction sites, areas previously detected with local DF cases and container terminals and cargo working areas in port areas, to intensify mosquito prevention and control work throughout winter. Closely following the thematic operation, the year-end clean-up operation will commence on January 11, 2019, during which mosquito control work will also be enhanced."
In addition, the FEHD set up four Pest Control Inspection Teams in May last year to step up inspection of construction sites and enforcement action against mosquito breeding. This year, as of November 18, the FEHD has instituted 191 prosecutions for mosquito breeding found in relevant premises under the Public Health and Municipal Services Ordinance (Cap 132), comprising 182 cases involving construction sites and nine cases involving other premises.
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 continue to carry out effective mosquito prevention and control measures, including inspecting their homes and surroundings to remove potential breeding grounds, scrubbing vases and pot plant saucers 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 fill up all depressions to prevent puddles from forming. They should also scrub all drains and surface sewers with an alkaline detergent compound 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, oviposition traps 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 does not capture the activity of Aedes albopictus outside the 57 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.