The Food and Environmental Hygiene Department (FEHD) today (May 11) released the first batch of gravidtrap indexes and density indexes for Aedes albopictus in May, covering 14 survey areas, as follows:
 

District	Survey Area	May 2026
		First Phase Gravidtrap Index	First Phase Density Index
Wan Chai	Tin Hau and Causeway Bay	7.8%	1.3
	Wan Chai	5.4%	1.3
Kowloon City	Kowloon City	7.4%	1.0
	Kowloon Tong	12.9%	1.3
Kwun Tong	Kwun Tong Central	13.6%	1.5
	Lam Tin and Sau Mau Ping	13.8%	1.1
Mong Kok	Mong Kok and Tai Kok Tsui	0.0%	N/A
Yau Tsim	Tsim Sha Tsui and Yau Ma Tei	4.7%	2.0
	Tsim Sha Tsui East and King's Park	9.1%	1.0
North	Fanling North	14.3%	1.0
	Fanling South	7.0%	1.7
Kwai Tsing	Tsing Yi South	12.3%	1.1
Tsuen Wan	Sheung Kwai Chung	7.4%	1.3
Yuen Long	Tin Shui Wai	8.0%	1.0

　　Among the first batch of First Phase Gravidtrap Indexes covering 14 survey areas in May, all were below 10 per cent, except for Kowloon Tong in Kowloon City District, Fanling North in North District, Tsing Yi South in Kwai Tsing District, as well as Kwun Tong Central, and Lam Tin and Sau Mau Ping in Kwun Tong 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 Kowloon Tong in Kowloon City District, Fanling North in North District, Tsing Yi South in Kwai Tsing District, as well as Kwun Tong Central, and Lam Tin and Sau Mau Ping in Kwun Tong 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 Kowloon Tong showed that areas with more mosquito problems included parks, schools and private housing estates; the gravidtrap data for Fanling North and Tsing Yi South showed that areas with more mosquito problems included parks and public and private housing estates; the gravidtrap data for Kwun Tong Central showed that areas with more mosquito problems included parks, schools and public housing estates; and the gravidtrap data for Lam Tin and Sau Mau Ping showed that areas with more mosquito problems included public and private housing estates.

　　In response to the high-risk areas identified in the said survey areas, the FEHD has issued three statutory notices to a relevant venue management company and estate management companies following the discovery of stagnant water in a park in Kowloon City District and two public housing estates in Kwun Tong District, 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.

　　Among these 14 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. Five 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/Monday, May 11, 2026
Issued at HKT 20:53

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