October's monthly ovitrap index for Aedes albopictus drops further

     The Food and Environmental Hygiene Department (FEHD) announced today (November 17) that the monthly territory-wide ovitrap index for Aedes albopictus dropped further, from 6.2 per cent in September to 2.8 per cent in October, indicating that the infestation of Aedes albopictus in the areas surveyed was not extensive.
     "Aedes albopictus is a kind of mosquito that can transmit dengue fever (DF) and Zika virus. Despite the relatively low level of October's monthly ovitrap index for Aedes albopictus recorded, in view of the fact that Hong Kong has recorded a confirmed local DF case, five local Japanese encephalitis (JE) cases and one imported case of Zika Virus Infection so far this year, as well as reports of Zika Virus Infection cases continuing in neighbouring areas where DF has also remained highly prevalent, the community must remain vigilant and continue to carry out effective mosquito control measures in the coming winter season," an FEHD spokesman said.
     Among the 52 areas surveyed last month, positive ovitrap indices were recorded in 30 areas, ranging from 1.6 per cent to 14.1 per cent, with the highest in Wong Tai Sin Central. As for the port areas, the monthly ovitrap index for Aedes albopictus for October also fell to 0.4 per cent from 1.6 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 launched a special territory-wide thematic mosquito prevention and control operation on October 30, which will continue in the winter season and last till January 19, 2018. Relevant departments will also participate 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, and intensify mosquito prevention and control work at those places in winter. Closely following the thematic operation will be the year-end clean-up operation, which will commence on January 22, 2018, during which mosquito control work will also be enhanced."
     The spokesman said that the FEHD had set up four Pest Control Inspection Teams in May to step up inspection of construction sites and enforcement action against mosquito breeding. This year, as of November 10, the FEHD has instituted 271 prosecutions for mosquito breeding found in relevant premises under the Public Health and Municipal Services Ordinance (Cap 132), comprising 257 cases involving construction sites and 14 cases involving other premises.
     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 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 52 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 52 areas and it also does not measure the prevalence of other kinds of mosquitoes.
     The ovitrap indices for Aedes albopictus of different areas and information on anti-mosquito measures are available on the department website at www.fehd.gov.hk.

Ends/Friday, November 17, 2017
Issued at HKT 16:00