The Food and Environmental Hygiene Department (FEHD) announced today (August 9) that it will enhance the dissemination of gravidtrap index data to allow more citizens to quickly grasp the mosquito infestation situation and strengthen mosquito control efforts, thereby reducing the risk of chikungunya fever (CF) transmission.

     The FEHD has previously announced the gravidtrap index data in July and is currently conducting mosquito infestation surveys in various survey areas for August. Once the surveys are completed in individual survey areas and the latest gravidtrap and density indices are available, the FEHD will disseminate the relevant information through press releases, its website, and social media.

     The first batch of gravidtrap index and density index for August, covering 13 survey areas, is as follows:
 

District	Survey Area	August 2025
		First Phase Gravidtrap Index	First Phase Density Index
Eastern	North Point	7.1%	1.0
Southern	Deep Water Bay and Repulse Bay	5.3%	1.0
Wanchai	Wan Chai North	0.0%	N/A
Yau Tsim	Tsim Sha Tsui	3.1%	1.0
	Tsim Sha Tsui East	7.4%	1.0
Kowloon City	Kowloon City North	5.6%	1.0
Wong Tai Sin	Wong Tai Sin Central	3.8%	1.0
Sha Tin	Tai Wai	1.6%	1.0
	Sha Tin East	4.8%	1.0
	Ma On Shan	6.5%	1.0
Tai Po	Tai Po East	3.9%	1.0
Tuen Mun	So Kwun Wat	16.4%	1.0
Kwai Tsing	Tsing Yi South	3.6%	1.0

     The index in So Kwun Wat, Tuen Mun District, reached 16.4 per cent. In response to the recent CF situation, the FEHD has activated a mechanism that strengthen mosquito control work in areas with the gravidtrap index between 10 per cent and 20 per cent, which was originally activated when the gravidtrap index reaches 20% or above. The FEHD will collaborate with relevant departments and stakeholders to identify locations with high mosquito infestation, and carry out intensive and targeted mosquito control measures. The FEHD will also organise exhibitions, distribute leaflets and posters, and notify the residential estates subscribed to the gravidtrap Rapid Alert System, advising property management agents and residents to stay vigilant and join hands in taking mosquito prevention and elimination measures.

     Members of public should adopt the following measures, strengthening the prevention against the breeding of mosquitoes:
 

• Tidy up their premises and check for any accumulation of water in containers inside their premises; 
• Remove all unnecessary water collection and eliminate the sources;
• Completely change the water in flower vases at least once a week and remove the water on the plant saucers;
• Properly cover all containers that hold water;
• Properly dispose of refuse, such as soft drink cans, empty bottles and boxes, in covered litter containers; and
• Level irregular ground surfaces and holes.

     Following the 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 of the two weeks' surveillance will be combined to obtain the Area Gravidtrap Index and the Area Density Index. The gravidtrap and density indices 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/Saturday, August 9, 2025
Issued at HKT 12:10

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