FEHD releases fifth batch of gravidtrap indexes for Aedes albopictus in December
The Food and Environmental Hygiene Department (FEHD) today (December 31) released the fifth batch of gravidtrap indexes and density indexes for Aedes albopictus in December, covering 15 survey areas, as follows:
District
Survey Area
December 2025
First Phase Gravidtrap Index
First Phase Density Index
Kowloon City
Hung Hom
1.8%
1.0
Kwun Tong
Kwun Tong Central
0.0%
N/A
Yau Tong and Cha Kwo Ling
0.0%
N/A
Yuen Long
Yuen Kong
0.0%
N/A
Ki Lun Shan
0.0%
N/A
Sung Shan
0.0%
N/A
Tsuen Wan
Tsuen Wan West
1.9%
1.0
Kwai Tsing
Tsing Yi South
0.0%
N/A
Tsing Yi North
0.0%
N/A
District
Survey Area
December 2025
Area Gravidtrap Index
Area Density Index
Eastern
Shau Kei Wan and Sai Wan Ho
0.0%
N/A
Islands
Cheung Chau South
1.4%
1.0
Kowloon City
Lok Fu West
0.0%
N/A
Kwun Tong
Kowloon Bay
0.0%
N/A
North
Fanling
0.0%
N/A
Tsuen Wan
Tsuen Wan Town
0.0%
N/A
Among the fifth batch of First Phase Gravidtrap Indexes covering nine survey areas and Area Gravidtrap Indexes covering six survey areas in December, all were below 10 per cent, and most of the areas recorded zero per cent, indicating that the distribution of Aedes albopictus mosquitoes was not extensive.
The FEHD has so far released five batches of gravidtrap indexes for Aedes albopictus in December 2025, covering 64 survey areas. Among these 64 survey areas, 60 recorded a decrease or remained unchanged in the individual gravidtrap index compared to the Area Gravidtrap Index last month, i.e. November 2025, representing that the areas' mosquito infestation improved or maintained a low level. Four other areas recorded a slight increase, but the indexes were lower than 10 per cent.
The eggs of Aedes albopictus can withstand long periods of desiccation and will hatch when the temperature becomes suitable and water is present. Members of the public should continue to take mosquito control measures during winter to eliminate mosquito eggs.
Public participation is crucial to the effective control of mosquito problems. The FEHD appeals to members of the public to continue to work together in strengthening personal mosquito control measures, including:
- tidy up their premises and check for any accumulation of water inside their premises;
- remove all unnecessary water collections and eliminate the sources;
- check household items (those placed in outdoor and open areas in particular), such as refuse containers, vases, air conditioner drip trays, and laundry racks to prevent stagnant water;
- change the water in flower vases and clear the water in saucers of potted plants at least once every seven days;
- properly cover all containers that hold water to prevent mosquitoes from accessing the water;
- properly dispose of articles that can contain water, such as empty lunch boxes and cans; and
- scrub drains and surface sewers with alkaline detergent at least once a week to remove any mosquito eggs.
Starting in August this year, following the completion of the surveillance of individual survey areas, and once the latest gravidtrap index and the density index are available, the FEHD has been disseminating relevant information through press releases, its website and social media. It aims to allow members of the public to quickly grasp the mosquito infestation situation and strengthen mosquito control efforts, thereby reducing the risk of chikungunya fever (CF) transmission.
Following recommendations from the World Health Organization and taking into account the local situation in Hong Kong, the FEHD sets up gravidtraps in districts where mosquito-borne diseases have been recorded in the past, as well as in densely populated places such as housing estates, hospitals and schools to monitor the breeding and distribution of Aedes albopictus mosquitoes, which can transmit CF and dengue fever. At present, the FEHD has set up gravidtraps in 64 survey areas of the community. During the two weeks of surveillance, the FEHD will collect the gravidtraps once a week. After the first week of surveillance, the FEHD will immediately examine the glue boards inside the retrieved gravidtraps for the presence of adult Aedine mosquitoes to compile the Gravidtrap Index (First Phase) and Density Index (First Phase). At the end of the second week of surveillance, the FEHD will instantly check the glue boards for the presence of adult Aedine mosquitoes. Data from the two weeks of surveillance will be combined to obtain the Area Gravidtrap Index and the Area Density Index. 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 webpage (www.fehd.gov.hk/english/pestcontrol/dengue_fever/Dengue_Fever_Gravidtrap_Index_Update.html#).
The Food and Environmental Hygiene Department (FEHD), Photo source: reference image
Update on chikungunya fever
The Centre for Health Protection (CHP) of the Department of Health announced that, as of 5pm today (December 31), no new cases of chikungunya fever (CF) had been recorded.
Latest surveillance data
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Hong Kong has recorded a total of 82 confirmed CF cases this year. Among them, 11 were local cases, and the rest were imported cases.
Since the beginning of 2025, and as of December 10, a total of 502 264 CF cases and 186 CF-related deaths have been reported in over 40 countries/territories. Cases have been reported in the Americas, Africa, Asia, and Europe. Although the northern hemisphere has entered the winter season, temperatures in subtropical and some temperate regions remain elevated due to climate change, creating favourable conditions for mosquito breeding. In addition, CF outbreaks continue to occur in many countries worldwide. The risk of imported cases persists. Members of the public should check the situation of the destinations before travelling abroad, especially when travelling to Southeast Asian countries.
Government's comprehensive follow-up actions
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Given that some local cases of CF have visited the Tsing Yi Nature Trails or the surrounding area in November, the trails are currently closed until further notice. Relevant government departments continue to conduct large-scale mosquito control and prevention efforts along the trails, and the CHP appeals to the public not to enter the area in order to reduce the risk of contracting CF and to avoid exposure to chemicals or interfering with the mosquito control operations. Since the confirmation on December 10 of a case involving a person who had visited the Tsing Yi Nature Trails on November 30, no further local cases have been recorded to date. The CHP continues to urge individuals who have recently hiked along the Tsing Yi Nature Trails to seek medical attention as soon as possible if they develop relevant symptoms and to call the enquiry hotline (Tel: 2125 2373), which operates from 9am to 6pm.
The Food and Environmental Hygiene Department (FEHD) has been continuously conducting intensive fogging operations to eliminate adult mosquitoes along the Tsing Yi Nature Trails and the surrounding area. At suitable locations, large ultra-low volume foggers have been deployed, and a robot dog is being put on trial to enhance operational effectiveness. The FEHD has also set up new mosquito trapping devices, cleared discarded containers and garbage that could cause stagnant water, and applied larvicide oil or larvicides in areas with stagnant water that cannot be removed immediately. The FEHD has been collaborating with the Kwai Tsing District Office, the Lands Department and the Drainage Services Department to strengthen efforts in eliminating potential mosquito breeding sites along the Tsing Yi Nature Trails. Pamphlets have been distributed to hikers in the area, urging citizens to be vigilant against mosquito infestations and take personal protective measures. The FEHD has also held meetings of the interdepartmental task forces on anti-mosquito work across districts to discuss the latest developments regarding the situation and plan accordingly to co-ordinate relevant departments and stakeholders in strengthening mosquito prevention and control measures in areas under their purview.
Continuously strengthening prevention and control
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The FEHD and relevant departments have comprehensively enhanced the mosquito control operations in Hong Kong since July this year, and this has continued. Among these, the FEHD has conducted vector investigations and targeted mosquito control operations against the imported and local cases. In light of the local case, the FEHD has immediately conducted follow-up actions, including:
carrying out intensive fogging in scrubby areas within a 250-metre radius of the relevant locations to kill adult mosquitoes;
carrying out inspections of the locations, removing stagnant water, applying insecticides and disposing of abandoned water containers every week with a view to preventing mosquito breeding; and
enhancing public education efforts through organising health talks, setting up mobile education stations, and distributing publicity leaflets.
The abovementioned measures will be continued. Furthermore, the Government will further enhance the mosquito control efforts in addition to the existing measures.
Preventive measures to be taken by the public
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Members of the public should use DEET-containing insect repellents or other effective active ingredients properly to prevent mosquito bites, but the following precautions should be taken when using them:
read the label instructions carefully first;
apply right before entering an area with a risk of mosquito bites;
apply on exposed skin and clothing;
use DEET of up to 30 per cent for pregnant women and up to 10 per cent for children (for children who travel to countries or areas where mosquito-borne diseases are endemic or epidemic and where exposure is likely, those aged 2 months or above can use DEET-containing insect repellents with a DEET concentration of up to 30 per cent);
apply sunscreen first, then insect repellent;
reapply only when needed and follow the instructions; and
in addition to DEET, there are other insect repellents available on the market containing different active ingredients, such as IR3535 and picaridin. When using any insect repellent, the public should follow the usage instructions and precautions on the product label.
The FEHD also 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 potted plants at least once a week, and properly disposing of containers such as empty cans and lunch boxes. The FEHD also advises members of the public and property management agencies 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 public should call 1823 in case of mosquito problems, and may visit the following pages for more information: the CF page of theCHPand theTravel Health Service, the latestTravel Health News,tips for using insect repellents, and the CHPFacebook Page,Instagram AccountandYouTube Channel, and also theMosquito Prevention and Control dedicated pageof the FEHD.
Source: AI-found images
