FEHD releases third batch of gravidtrap indexes for Aedes albopictus in May (with photos)
The Food and Environmental Hygiene Department (FEHD) today (May 19) released the third batch of gravidtrap indexes and density indexes for Aedes albopictus in May, covering 19 survey areas, as follows:
| District | Survey Area | May 2026 | |
| First Phase Gravidtrap Index | First Phase Density Index | ||
| Southern | Pok Fu Lam | 13.8% | 1.1 |
| Kowloon City | Ho Man Tin | 25.0% | 1.2 |
| Kwun Tong | Yau Tong and Cha Kwo Ling | 28.8% | 1.8 |
| Wong Tai Sin | Wong Tai Sin West | 24.5% | 1.6 |
| Sha Tin | Sha Tin Town Centre and Fo Tan | 18.2% | 1.4 |
| Tai Wai | 46.0% | 1.7 | |
| Tsuen Wan | Ma Wan and Sham Tseng | 31.5% | 1.8 |
| District | Survey Area | May 2026 | |
| Area Gravidtrap Index | Area Density Index | ||
| Wan Chai | Tin Hau and Causeway Bay | 8.8% | 1.3 |
| Wan Chai | 5.5% | 1.3 | |
| Islands | Cheung Chau | 12.0% | 1.5 |
| Kowloon City | Kowloon City | 10.3% | 1.0 |
| Kwun Tong | Lam Tin and Sau Mau Ping | 27.7% | 1.7 |
| Mong Kok | Mong Kok and Tai Kok Tsui | 0.9% | 1.0 |
| Wong Tai Sin | Wong Tai Sin East | 16.7% | 1.3 |
| Yau Tsim | Tsim Sha Tsui East and King's Park | 9.1% | 1.4 |
| North | Fanling South | 14.9% | 1.4 |
| Kwai Tsing | Tsing Yi South | 15.0% | 1.1 |
| Tuen Mun | Tuen Mun North | 9.4% | 1.1 |
| Yuen Long | Tin Shui Wai | 13.0% | 1.0 |
The third batch of gravidtrap indexes for Aedes albopictus in May includes First Phase Gravidtrap Indexes covering seven survey areas and Area Gravidtrap Indexes covering 12 survey areas. Among which, 14 survey areas recorded gravidtrap indexes above 10 per cent, while Ho Man Tin in Kowloon City District; Yau Tong and Cha Kwo Ling, and Lam Tin and Sau Mau Ping in Kwun Tong District; Wong Tai Sin West in Wong Tai Sin District; Tai Wai in Sha Tin District; as well as Ma Wan and Sham Tseng in Tsuen Wan District, recorded gravidtrap indexes above 20 per cent.
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 and extent of the rise are affected by factors like weather conditions and rainfall. The average temperature and rainfall recorded in April this year were higher than those in the same period last year, creating favourable conditions for mosquito growth and breeding. As a result, the rise in gravidtrap indexes occurred earlier this year. With the increase in rainfall in the first half of May, the gravidtrap indexes are expected to rise further.
For survey areas 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. Moreover, the FEHD has initiated three prosecutions against the relevant construction site contractor, estate management company and property management company following the discovery of mosquito breeding at a construction site, a public housing estate and a private housing estate in Sha Tin District and Tsuen Wan District. Furthermore, following the discovery of stagnant water or stagnant water containers at a total of four parks, a construction site, four public housing estates, four private housing estates, a school and two private premises in Kowloon City District, Kwun Tong District, Wong Tin Sin District, Sha Tin District, Tsuen Wan District and Yuen Long District, the FEHD has issued 16 statutory notices to the relevant venue management companies, a construction site contractor, estate management companies, property management companies and responsible persons of private premises, requiring the clearance of such items within a specified timeframe. The FEHD also issued a warning letter to a school in Wong Tai Sin District following the discovery of potential mosquito problems. The FEHD, the relevant departments and stakeholders 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.
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 the 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/Tuesday, May 19, 2026
The Food and Environmental Hygiene Department (FEHD) today (May 19) released the third batch of gravidtrap indexes and density indexes for Aedes albopictus in May, covering 19 survey areas. Photo shows an FEHD staff member inspecting a construction site in Yau Tong and Cha Kwo Ling in Kwun Tong District. Following the discovery of stagnant water containers in the construction site, a statutory notice has been issued to the relevant construction site contractor, requiring the clearance of such items within a specified period.
The Food and Environmental Hygiene Department (FEHD) today (May 19) released the third batch of gravidtrap indexes and density indexes for Aedes albopictus in May, covering 19 survey areas. Photo shows an FEHD staff member inspecting a park in Wong Tai Sin West, Wong Tai Sin District, to provide management staff member with advice and technical support on mosquito prevention and control.
The Food and Environmental Hygiene Department (FEHD) today (May 19) released the third batch of gravidtrap indexes and density indexes for Aedes albopictus in May, covering 19 survey areas. Photo shows FEHD staff members inspecting a new mosquito trap at a public housing estate in Tai Wai, Sha Tin District, to provide property management staff members with advice and technical support on mosquito prevention and control.
The Food and Environmental Hygiene Department (FEHD) today (May 19) released the third batch of gravidtrap indexes and density indexes for Aedes albopictus in May, covering 19 survey areas. Photo shows a staff member of the FEHD's contractor conducting a fogging operation to eradicate adult mosquitoes in the vicinity of Ma Wan, Tsuen Wan District.