September monthly ovitrap index continues to fall
"Aedes albopictus is a kind of mosquito that can transmit dengue fever (DF) and Zika virus. In view of four confirmed local DF cases and the first imported case of Zika Virus Infection recorded in Hong Kong since August, and the fact that DF is still highly prevalent with emerging new Zika cases in neighbouring areas, the community must continue to carry out effective mosquito control measures in autumn," an FEHD spokesman said.
Among the 52 areas surveyed last month, only the Area Ovitrap Indexes (AOI) in Kai Tak North (23.7 per cent) and Pokfulam (23.1 per cent) exceeded the alert level of 20 per cent. The spokesman said an inter-departmental anti-mosquito response mechanism has been activated in the above-mentioned areas. In addition to the routine anti-mosquito programme, the FEHD will clear potential mosquito breeding grounds in the public places in the areas and apply larvicides to stagnant water where appropriate. It will also handle mosquito complaints promptly and take out prosecutions under the relevant ordinance against mosquito breeding.
The government departments concerned have also stepped up inspections and measures to enhance environmental hygiene in areas within their ambits. The aim is to eliminate existing and potential mosquito breeding grounds.
"Furthermore, relevant departments have individually notified the groups that had voluntarily subscribed to the ovitrap rapid alert system when the AOI reached the alert level of 20 per cent. Subscribers have been invited to post specially designed alert notices in the common parts of their premises to urge occupants and staff to take mosquito prevention and control measures promptly," the spokesman said.
As for the port areas, the monthly ovitrap index for Aedes albopictus for September also dropped slightly to 2.1 per cent from 2.2 per cent in August.
To sustain mosquito prevention and control work effectively, the FEHD and relevant government departments have been conducting intensive mosquito preventive and control exercises across the territory covering areas under their purview from August 1 to October 31. During the exercises, actions will be taken to kill adult mosquitoes, clear stagnant water and conduct grass cutting to eliminate potential mosquito breeding grounds, as well as to enhance publicity and public education on mosquito control via various channels. With these exercises, it is hoped that a whole generation of mosquitoes, including those that may be infected, will be eliminated.
During the above period, the FEHD has also enhanced its routine dengue vector surveillance programme to monitor the vector for Zika virus as well. All local mosquito samples collected from port areas and areas with an AOI reaching 10 per cent or above in the community will be tested for DF and Zika virus. In the case of positive results, mosquito control measures will be strengthened in areas within a 500-metre radius of the ovitrap concerned.
Meanwhile, to intensify mosquito prevention and control work, the FEHD will launch a special territory-wide thematic mosquito prevention and control operation on October 31, which will last until December 30. During the period, 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 handling areas in port areas, and intensify mosquito prevention and control work at those places. Relevant departments will also participate in this special anti-mosquito operation.
As Aedes albopictus breeds in small water bodies, the spokesman reminded members of the public to inspect their homes and surroundings to remove potential breeding grounds, scrub vases and pot plant saucers at least once a week, properly dispose of containers such as soft drink cans and lunch boxes, and drill large holes in unused tyres. He also advised 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 take 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 efforts of all parties concerned. The community must work together with the Government to take 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 52 areas in Hong Kong for monitoring the breeding of Aedes albopictus, which is 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 52 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 anti-mosquito measures are available on the department website at www.fehd.gov.hk.
Ends/Thursday, October 20, 2016
Issued at HKT 17:47
Issued at HKT 17:47