FEHD releases second batch of gravidtrap indexes for Aedes albopictus in May (with photos)
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| District | Survey Area | May 2026 | |
| First Phase Gravidtrap Index | First Phase Density Index | ||
| Central and Western | Kennedy Town and Shek Tong Tsui | 20.8% | 1.2 |
| Eastern | Chai Wan | 11.5% | 1.0 |
| North Point and Quarry Bay | 24.6% | 1.5 | |
| Southern | Aberdeen and Ap Lei Chau | 31.5% | 1.9 |
| Islands | Cheung Chau | 9.3% | 1.4 |
| Wong Tai Sin | Wong Tai Sin East | 17.0% | 1.3 |
| Tsuen Wan | Tsuen Wan Town | 8.8% | 2.4 |
| Tuen Mun | Tuen Mun North | 9.5% | 1.2 |
| District | Survey Area | May 2026 | |
| Area Gravidtrap Index | Area Density Index | ||
| Kowloon City | Kowloon Tong | 23.4% | 1.4 |
| Kwun Tong | Kwun Tong Central | 37.3% | 2.2 |
| Yau Tsim | Tsim Sha Tsui and Yau Ma Tei | 4.8% | 2.0 |
| North | Fanling North | 13.1% | 1.5 |
| Tsuen Wan | Sheung Kwai Chung | 10.3% | 1.5 |
Among the second batch of First Phase Gravidtrap Indexes covering eight survey areas and Area Gravidtrap Indexes covering five survey areas in May, all were below 10 per cent, except for Kennedy Town and Shek Tong Tsui in Central and Western District; Chai Wan, North Point and Quarry Bay in Eastern District; Aberdeen and Ap Lei Chau in Southern District; Wong Tai Sin East in Wong Tai Sin District; Kowloon Tong in Kowloon City District; Kwun Tong Central in Kwun Tong District; Fanling North in North District; as well as Sheung Kwai Chung in Tsuen Wan District.
With reference to the data from the past few years, the gravidtrap indexes start to rise from April or May every year. The actual timing of the increase and its extent are affected by factors like weather and rainfall. Entering the humid and rainy season, the conditions are favourable for mosquito growth and breeding, and the overall trend and extent of the rise of gravidtrap indexes this year are similar to those of previous years. In response to the rise of gravidtrap indexes, the FEHD, together with relevant departments and stakeholders, has implemented rapid response measures and deployed targeted actions.
For Kennedy Town and Shek Tong Tsui in Central and Western District; Chai Wan, North Point and Quarry Bay in Eastern District; Aberdeen and Ap Lei Chau in Southern District; Wong Tai Sin East in Wong Tai Sin District; Kowloon Tong in Kowloon City District; Kwun Tong Central in Kwun Tong District; Fanling North in North District; as well as Sheung Kwai Chung in Tsuen Wan District, which recorded indexes exceeding 10 per cent, in accordance with the mechanism implemented by the FEHD in response to the chikungunya fever (CF) situation (i.e. strengthening mosquito control work in areas with a gravidtrap index between 10 per cent and 20 per cent, instead of 20 per cent or above under the original mechanism), the FEHD is collaborating with relevant departments and stakeholders to identify locations with high mosquito infestations and carry out intensive and targeted mosquito control measures. In particular, the gravidtrap data for Chai Wan showed that areas with more mosquito problems included hospitals, parks and public and private housing estates; the gravidtrap data for North Point and Quarry Bay showed that areas with more mosquito problems included parks and public and private housing estates; the gravidtrap data for Fanling North showed that areas with more mosquito problems included parks, public and public housing estates and village houses; the gravidtrap data for Kowloon Tong showed that areas with more mosquito problems included parks, schools and private housing estates; and the gravidtrap data for Kennedy Town and Shek Tong Tsui, Aberdeen and Ap Lei Chau, Wong Tai Sin East, Kwun Tong Central and Sheung Kwai Chung showed that areas with more mosquito problems included parks, schools and public and private housing estates.
In response to the high-risk areas identified in the said survey areas, the FEHD has initiated three prosecutions against relevant construction site contractors following the discovery of mosquito breeding at construction sites in Southern District, Kowloon City District and Kwun Tong District. Furthermore, following the discovery of stagnant water or stagnant water containers at a total of five parks, a construction site, three public housing estates and two private housing estates in Central and Western District, Kowloon City District, Kwun Tong District and Tsuen Wan District, the FEHD has issued 11 statutory notices to the relevant venue management companies, construction site contractors, estate management companies and property management companies, requiring the clearance of such items within a specified timeframe. The FEHD and the relevant departments are following up on the mosquito control work, and will also organise exhibitions, distribute leaflets and posters, and notify residential estates that have subscribed to the gravidtrap Rapid Alert System, advising property management agents and residents to stay vigilant and work together in taking mosquito prevention and elimination measures. In addition, the FEHD will strengthen the monitoring of the gravidtrap index in the areas to review the effectiveness of the mosquito control work.
The FEHD has so far released two batches of gravidtrap indexes for Aedes albopictus in May 2026, covering 22 survey areas. Among these 22 survey areas, four recorded a decrease or remained unchanged as compared to the Area Gravidtrap Index last month (i.e. April 2026), representing that the areas' mosquito infestation improved or maintained a low level. Seven other areas recorded a slight increase, but the indexes were lower than 10 per cent.
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 water in flower vases and scrub their inner surfaces thoroughly, and remove water in saucers under potted plants at least once a week;
- properly cover all containers that hold water to prevent mosquitoes from accessing the water;
- properly dispose of articles that can contain water, such as disposable meal boxes and empty cans; and
- scrub drains and surface sewers with alkaline detergent at least once a week to remove any mosquito eggs.
Starting in August 2025, 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 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 62 survey areas of the community, with a surveillance period of two weeks. During the surveillance period, 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#).
Ends/Thursday, May 14, 2026
Issued at HKT 14:00
Issued at HKT 14:00
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