FEHD releases third batch of gravidtrap indexes for Aedes albopictus in April (with photos)
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| District | Survey Area | April 2026 | |
| First Phase Gravidtrap Index | First Phase Density Index | ||
| Central and Western | Kennedy Town and Shek Tong Tsui | 7.7% | 1.0 |
| Eastern | Chai Wan | 8.1% | 1.0 |
| Shau Kei Wan and Sai Wan Ho | 10.7% | 1.5 | |
| Wan Chai | Happy Valley and Tai Hang | 1.8% | 1.0 |
| Islands | Tung Chung | 2.0% | 1.0 |
| Kowloon City | Ho Man Tin | 3.6% | 1.0 |
| Kowloon Tong | 8.5% | 1.4 | |
| Sham Shui Po | Cheung Sha Wan | 7.5% | 1.3 |
| Lai Chi Kok | 7.0% | 1.0 | |
| Sham Shui Po and Shek Kip Mei | 4.9% | 1.0 | |
| Yau Tsim | Tsim Sha Tsui and Yau Ma Tei | 4.8% | 1.0 |
| North | Fanling North | 0.0% | N/A |
| Sai Kung | Tseung Kwan O East | 7.3% | 1.0 |
| Tseung Kwan O North | 11.4% | 1.6 | |
| Tseung Kwan O West | 3.6% | 1.0 | |
| Tai Po | Tai Po West | 1.8% | 1.0 |
| Tsuen Wan | Sheung Kwai Chung | 3.7% | 1.0 |
| Tuen Mun | Tuen Mun South | 14.5% | 1.0 |
| Yuen Long | Yuen Long Town | 3.4% | 1.5 |
| District | Survey Area | April 2026 | |
| Area Gravidtrap Index | Area Density Index | ||
| Central and Western | Sheung Wan and Sai Ying Pun | 3.5% | 1.0 |
| Southern | Pok Fu Lam | 4.3% | 1.0 |
| Wong Tai Sin | Wong Tai Sin West | 2.8% | 1.0 |
| Sai Kung | Sai Kung Town | 16.8% | 1.4 |
| Kwai Tsing | Lai King | 6.6% | 1.0 |
| Yuen Long | Hung Shui Kiu and Ping Shan | 3.2% | 1.3 |
Among the third batch of First Phase Gravidtrap Indexes covering 19 survey areas and Area Gravidtrap Indexes covering six survey areas in April, all were below 10 per cent, except for the First Phase Gravidtrap Indexes of Shau Kei Wan and Sai Wan Ho in Eastern District, Tseung Kwan O North in Sai Kung District, and Tuen Mun South in Tuen Mun District, as well as the Area Gravidtrap Index of Sai Kung Town in Sai Kung District.
For Shau Kei Wan and Sai Wan Ho in Eastern District, Tseung Kwan O North and Sai Kung Town in Sai Kung District, and Tuen Mun South in Tuen Mun 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 Shau Kei Wan and Sai Wan Ho showed that areas with more mosquito problems included parks, schools and private housing estates; the gravidtrap data for Tseung Kwan O North showed that areas with more mosquito problems included parks, schools, and public and private housing estates; the gravidtrap data for Sai Kung Town showed that areas with more mosquito problems included parks, sports grounds, schools, and public and private housing estates; and the gravidtrap data for Tuen Mun South showed that areas with more mosquito problems included parks and public housing estates. 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 three batches of gravidtrap indexes for Aedes albopictus in April 2026, covering 33 survey areas. Among these 33 survey areas, three recorded a decrease or remained unchanged as compared to the Area Gravidtrap Index last month (i.e. March 2026), representing that the areas' mosquito infestation improved or maintained a low level. Twenty-five other areas recorded a slight increase, but the indexes were lower than 10 per cent.
The average temperature and rainfall in April this year were higher than those of the same period last year, creating favourable conditions for mosquito growth and breeding. The latest First Phase Gravidtrap Index recorded in Sheung Shui reached 21.3 per cent, corresponding to Level 3 alert level. Indexes in other survey areas are also expected to rise. The FEHD has implemented rapid response measures and deployed targeted actions. Members of the public should also step up mosquito prevention efforts and eliminate potential mosquito breeding sites in advance, thereby reducing the risk of mosquito-borne disease transmission.
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 DF. 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, April 23, 2026
Issued at HKT 15:00
Issued at HKT 15:00
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