September’s monthly gravidtrap index for Aedes albopictus drops

     The Food and Environmental Hygiene Department (FEHD) today (October 18) announced that the monthly gravidtrap index for Aedes albopictus (MGI) in September dropped to 5.7 per cent from 8.5 per cent in August and was at Level 2, indicating that distribution of Aedes albopictus in the areas surveyed was fairly extensive but remained at a relatively low level.

     Among the 64 survey areas, the area gravidtrap index (AGI) in Kai Tak North and Ma On Shan exceeded the alert level of 20 per cent. The gravidtraps concerned were mostly located 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, including the Housing Department, the Education Bureau and the Leisure and Cultural Services Department, by taking action to strengthen mosquito prevention and control work in the areas concerned. Moreover, the monthly density index for Aedes albopictus (MDI) in September was 1.2, which represented that an average of 1.2 Aedes albopictus adults were 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 September was 0.7 per cent, while the port monthly density index in September was 1.1, both remaining at a low level. 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. Relevant government departments will continue to intensify mosquito prevention and control work covering venues under their purview.

     A spokesman for the FEHD 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, the temperature of autumn is relatively high with rain and is favourable for mosquito breeding, 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.