The Food and Environmental Hygiene Department (FEHD) today (February 17) announced that the monthly gravidtrap index for Aedes albopictus (MGI) for January further dropped to 0.1 per cent from 0.7 per cent in December last year. The index in January remains lowest at Level 1, indicating that mosquito infestation in the areas surveyed was not extensive.
To enhance dengue vector surveillance, the FEHD has increased the number of survey areas from 62 to 64 from January this year, adding Sung Shan area, where a local dengue case was recorded last year, and splitting Tai Po North into Tai Po East and Tai Po West.
Among the 64 survey areas, no area was recorded with gravidtrap indices exceeding the alert level of 20 per cent. Moreover, the monthly density index for Aedes albopictus (MDI) in January remained at 1 as in December last year, which represented that an average of one Aedes albopictus adult was found in the Aedes-positive gravidtraps, indicating that the number of adult Aedes albopictus was not high in the areas surveyed. The FEHD reminded the public that despite the index remaining at a low level, the department appealed to the public to carry out early effective preventive measures against mosquito breeding as the warm and humid weather of spring is favourable for mosquito breeding.
As for the port areas, the port monthly gravidtrap index in January dropped further to 0.02 per cent from 0.1 per cent in December last year, while the port monthly density index in January is 1 as in December last year.
"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. The FEHD will conduct a three-phase Anti-mosquito Campaign this year. The first phase of the territory-wide campaign, lasting for four weeks, will start on February 22 until March 19. During the period, mosquito prevention and control work will be enhanced by the FEHD and relevant government departments. The district offices of the FEHD will target areas which have drawn particular concern, such as locations in close proximity to human residences, schools, construction sites, public housing estates, hospitals, illegal cultivation sites, waterfront public and private cargo working areas, cross boundary check points, typhoon shelters and cross boundary ferry terminals to remove accumulation of water and to carry out mosquito prevention and control work. The FEHD will, after the first and second phases of the campaign, conduct territory-wide thematic mosquito prevention and control special operations so as to enhance the effectiveness of the campaign," a spokesman for the FEHD said.
The area gravidtrap index (AGI) and the area density index (ADI) indicate the extensiveness of distribution and the density of Aedine mosquitoes respectively in that particular survey area, while the MGI and the MDI are enumerated by pooling together all AGIs and ADIs of the same month, which reflect the general situation of Aedes albopictus in all survey areas. The gravidtrap and density indices for Aedes albopictus in different areas and information on mosquito prevention and control measures are available on the department's website at www.fehd.gov.hk.
The spokesman said, "Aedes albopictus is a kind of mosquito that can transmit dengue fever (DF) as well as Zika virus infection. DF is commonly found in tropical and subtropical regions of the world, and has become endemic in many countries in Southeast Asia. As Hong Kong has recorded one local DF case last year and the dengue activity in neighbouring areas has remained high, while the weather will turn even warmer and more humid in spring which will be conducive to large-scale mosquito breeding in a short period of time, the community should stay vigilant and continue to carry out effective mosquito prevention and control measures."
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 the water in vases and scrubbing the inner surfaces, 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.
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.