The Food and Environmental Hygiene Department (FEHD) today (November 12) announced that the monthly gravidtrap index (MGI) for Aedes albopictus mosquitoes in October was 2.9 per cent, lower than the 5.2 per cent in September. This reflects the efforts by the FEHD and relevant government departments to intensify mosquito prevention and elimination operations, resulting in the further improvement of the overall mosquito infestation situation this month. 
 
     In October, among the 62 survey areas, all recorded an area gravidtrap index (AGI) lower than the alert level of 20 per cent. The decreases in the MGI and the AGI are attributable to the continuous and intensified mosquito prevention and elimination operations by various government departments and stakeholders, and may also have been affected by factors such as weather. Overall, the MGI for Aedes albopictus mosquitoes in October was 2.9 per cent, at Level 1 (indicating the distribution of Aedes albopictus mosquitoes in the survey areas was not extensive). Relevant departments and stakeholders will persistently intensify mosquito prevention and elimination operations.

     Moreover, the monthly density index for Aedes albopictus in October was 1.1, which represented that an average of 1.1 Aedes albopictus adults were found in the Aedes-positive gravidtraps, indicating that the number of adult Aedes albopictus was not abundant in the survey areas. The gravidtrap and density indexes for Aedes albopictus in different survey areas, as well as information on mosquito prevention and control measures, are available on the department's website at www.fehd.gov.hk.

     A spokesman for the FEHD said, "Since August last year, the FEHD has extended its intensified mosquito control work, which was originally initiated when the AGI of an area had reached 20 per cent (Level 3), to cover areas with the AGI falling between 10 and 20 per cent (Level 2). The continuous drop in gravidtrap indexes in recent months has reflected that the overall situation of mosquito infestation is under control. Nevertheless, cases of dengue fever (DF) and chikungunya fever (CF) were still recorded in neighbouring areas, meaning the risk of imported mosquito-borne diseases and secondary transmission remains. The FEHD will maintain the current arrangements, initiating intensified mosquito control work whenever the AGI of an area reaches 10 per cent or above, until further notice."

     The spokesman added, "Last year, in response to the CF situation, the FEHD strengthened information dissemination by announcing area indexes in batches through press releases, in addition to publishing the AGI on its webpage. Starting from this November, the FEHD will resume releasing the monthly gravidtrap and density indexes for Aedes albopictus, as well as relevant information on mosquito prevention through monthly press releases and social media upon completing the gravidtrap surveillance and consolidated analysis every month, enabling members of the public to grasp the overall condition of mosquito infestation. The FEHD will also continue to regularly publish the latest AGI on the department's webpage."

     The spokesman reminded that although autumn has arrived, the weather remains warm with occasional showers, which is favourable for mosquito breeding. The FEHD continues to execute mosquito prevention and control measures in all districts, and will implement rapid response measures and deploy targeted actions together with relevant departments and stakeholders to intensify the mosquito prevention and control work in areas under the purview of the relevant government departments, including eliminating mosquito breeding places, applying larvicides, conducting fogging operations to eradicate adult mosquitoes, and placing mosquito trapping devices at suitable locations. The FEHD will also conduct site inspections with relevant departments, and provide them with professional advice and technical support to assist them in formulating and implementing effective anti-mosquito measures swiftly. At the same time, the FEHD has strengthened publicity and education. The FEHD will closely monitor the mosquito infestation and the effectiveness of mosquito control work in various districts, dynamically adjust prevention and control strategies in accordance with actual circumstances, and implement targeted mosquito prevention and elimination measures.
 
     The FEHD continues to conduct a three-phase Anti-mosquito Campaign this year. The third phase of the Anti-mosquito Campaign ended on October 23. During the period, the district offices of the FEHD targeted residences, schools, construction sites, public housing estates, hospitals, illegal cultivation sites, waterfront public and private cargo working areas, land boundary control points, typhoon shelters and cross-boundary ferry terminals to remove accumulated water and carry out mosquito prevention and control work. To further enhance the effectiveness of mosquito control, the FEHD and relevant government departments launched the first and second phases of the All-out Anti-mosquito Operations on March 25 and April 30 respectively. Relevant departments will continue with the work of phase one, including eliminating potential mosquito breeding places and arranging for necessary structural repairs to minimise mosquito breeding places, and will consistently carry out the work of phase two by conducting regular ultra-low volume fogging operations at places with mosquito infestation to control the mosquitoes. The FEHD calls on property management entities to continue actively participating in the All-out Anti-mosquito Operations. 

     The FEHD appeals to members of the public to continue to stay alert and work together to carry out mosquito prevention and control measures early, including inspecting their homes and surroundings to remove potential breeding grounds, changing water in vases and scrubbing their inner surfaces, removing water in saucers under plant pots at least once a week, and properly disposing of containers such as empty cans and disposable meal boxes. The FEHD also advises members of the 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. 

     Aedes albopictus is a kind of mosquito that can transmit DF and CF. DF and CF are commonly found in countries in tropical and subtropical regions, and the risk of importation persists in many countries in Southeast Asia. The FEHD calls on members of the public to check the situation at their destinations before travelling abroad, especially when travelling to Southeast Asian countries. If travellers feel unwell after returning to Hong Kong, they should seek medical advice immediately and provide their travel history to the doctor.

Ends/Thursday, November 12, 2026
Issued at HKT 17:15

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