May’s monthly gravidtrap index for Aedes albopictus remains at Level 2

     The Food and Environmental Hygiene Department (FEHD) today (June 16) announced that the monthly gravidtrap index for Aedes albopictus (MGI) in May was 10.5 per cent, at Level 2, indicating that the distribution of Aedes albopictus in the areas surveyed was fairly extensive but maintained at a relatively low level. Relevant government departments have stepped up mosquito prevention and control actions.

     Among the 64 survey areas last month, the area gravidtrap index (AGI) in five areas (namely Ma On Shan, Lok Fu West, Ngau Liu and Muk Min Shan, Kowloon Bay and Tseung Kwan O North) exceeded the alert level of 20 per cent. The gravidtraps were mostly found in the vicinity of public and private residential areas, schools, recreational and sports facilities and public places. The FEHD has collaborated with relevant government departments by taking immediate action to strengthen mosquito prevention and control work in the areas concerned. Moreover, the monthly density index for Aedes albopictus (MDI) in May was 1.3, which represented that an average of 1.3 Aedes albopictus adults was found in the Aedes-positive gravidtraps, indicating that the number of adult Aedes albopictus was not high in the areas surveyed. As for the port areas, the port monthly gravidtrap index in May was 1.9 per cent, while the port monthly density index in May was 1.1, both remaining at a low level.

     The FEHD reminded the public to carry out effective prevention and control measures against mosquitoes as the hot and rainy summer weather will help mosquitoes to breed quickly. Relevant government departments have also commenced the All-out Anti-mosquito Operations on April 12, during which mosquito breeding places have been cleaned up and fogging has been conducted to kill adult mosquitoes in order to enhance anti-mosquito work.

     "Relevant government departments will continue to intensify mosquito prevention and control work covering venues under their purview. Apart from strengthening publicity and education, the FEHD is conducting a three-phase territory-wide Anti-mosquito Campaign this year. The second phase, lasting for nine weeks, has been launched in April and will run until June 18. During the period, the FEHD and relevant government departments will enhance the mosquito prevention and control work and target areas which have drawn particular concern, such as locations in close proximity to human residences, parks, schools, construction sites, public housing estates, hospitals, illegal cultivation sites, waterfront public and private cargo working areas, cross-boundary checkpoints, typhoon shelters and cross-boundary ferry terminals to remove the accumulation of water and to carry out mosquito prevention and control work. The FEHD will, after the second phase 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 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. The dengue activity in neighbouring areas has remained high and Hong Kong has recorded one imported DF case so far this year. Also, Hong Kong's hot and rainy summer is conducive to the proliferation of mosquitoes, so 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 public and estate management bodies to keep drains free of blockage and level all defective ground surfaces to prevent the 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.