The Centre for Health Protection (CHP) of the Department of Health (DH) is today (April 21) investigating the first local case of dengue fever (DF) in Hong Kong this year, and is working with various government departments to implement appropriate prevention and control measures. As temperatures gradually rise and humidity increases, creating favourable conditions for mosquito breeding, members of the public should take appropriate measures to prevent mosquito bites and mosquito breeding, both in Hong Kong and when travelling to areas affected by mosquito-borne diseases, in order to prevent mosquito-borne diseases.
 
Case details
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     The case involves a 21-year-old male with good past health. He developed a fever, headache, myalgia and a rash on April 12, and sought medical attention at Alice Ho Miu Ling Nethersole Hospital on April 16. He was admitted for treatment and is currently in stable condition. His blood sample tested positive for dengue virus upon laboratory testing.
      
     Initial investigations revealed that the patient lives in Tai Wo Estate in Tai Po and works at a road construction site near Long Yan Road in Penny's Bay on Lantau Island. He had no travel history during the incubation period (March 29 to April 9). During this period, he mainly stayed in the vicinity of the construction site in Penny's Bay and his home. He reported being bitten by mosquitoes recently near his workplace. He did not recall being bitten by mosquitoes in any other places, including Tai Wo Estate in Tai Po. His household contacts and other workers at the same construction site are currently asymptomatic. The CHP's investigation is ongoing and no epidemiological linkage has been found so far between this case and other previously recorded imported DF cases in Hong Kong.
           
     Including the above cases, a total of 13 DF cases have been recorded so far this year. All cases other than the one mentioned above were imported. Last year (2025), 59 DF cases were recorded, all of which were imported. In 2024, 161 DF cases were recorded, including 156 imported cases and five local cases.
 
Government's comprehensive follow-up actions
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     "The DH is conducting comprehensive follow-up actions in collaboration with relevant departments, including the Food and Environmental Hygiene Department (FEHD), the Housing Department, the Tai Po District Office and the Labour Department. The CHP has conducted inspections and epidemiological investigations in the vicinity of patient's residence and his workplace. Environmental inspections revealed that the area near the road construction site on Long Yan Road in Penny's Bay is a natural green space with multiple sites conducive to mosquito breeding, including drainage channels clogged with weeds and dead leaves, as well as stagnant water in some containers and construction equipment. The First Phase Area Gravidtrap Index for the patient's residential estate area (Tai Po West) in April is 1.8 per cent, which is an extremely low level. Based on the information available at the moment, it is more likely that the patient was infected in the vicinity of Long Yan Road in Penny's Bay. The CHP will continue to investigate the source of infection in collaboration with the FEHD. Additionally, the CHP has instructed the site supervisor to suspend work temporarily until mosquito control and other preventive measures have been completed at the site and its surrounding area. The CHP has conducted health assessments for the workers at the same construction site and they will continue to be placed under medical surveillance," said the Controller of the CHP, Dr Edwin Tsui.
      
     "As the patient had been active in the Tai Wo Estate after the onset of his illness, the CHP will, as a precautionary measure, set up a health consultation booth at Tai Wo Plaza in Tai Wo Estate. The health consultation booth provides health assessments and conducts free DF antibody tests for members of the public with relevant symptoms. The health consultation booth opens until 8pm today. From tomorrow (April 22) until Friday (April 24), the service hours of the health consultation booth will be from 10am to 7pm. The CHP has also set up a hotline (tel: 2125 2373), which will operate until 8pm today and from 9am to 6pm starting tomorrow until Friday. The CHP staff will distribute leaflets with health information on DF prevention to local residents and remind the public to be aware of the relevant symptoms and to maintain good hygiene at home. The CHP will jointly organise a health talk with the Tai Po District Office and the FEHD at the Tai Wo Neighbourhood Community Centre at 6pm tomorrow, aiming to raise public awareness of how to prevent mosquito-borne diseases and encourage people to participate in prevention and control measures to protect themselves and others. The CHP will also send a letter to doctors, hospitals, schools and institutions explaining the latest situation regarding DF and reminding them to remain vigilant. If there are any suspected cases, they should immediately notify the CHP for follow-up. Finally, I would like to remind the public to stay vigilant and take proper mosquito control and personal protective measures both locally and when travelling. According to surveillance data of the Aedes mosquito from the FEHD, the period from April to June is typically the peak season for mosquito infestations. Therefore, we anticipate that the risk of local transmission triggered by imported cases will rise significantly in the coming months," Dr Tsui added.
      
     In light of the local case, the FEHD has immediately taken follow-up actions, including:
 

• carrying out vector investigations and mosquito control operations, including removing stagnant water, applying insecticides and fogging in scrubby areas within a 250-metre radius of the relevant locations to kill adult mosquitoes;
• strengthening inspections of the high-risk locations and providing departments and the industry with professional advice and technical support; and
• enhancing public education efforts through organising health talks, setting up mobile education stations, and distributing publicity leaflets, to raise public awareness of mosquito prevention and control.

 
     The abovementioned measures will be continued. Furthermore, the Government will further enhance the mosquito control efforts in addition to the existing measures.
 
Preventive measures to be taken by the public
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     Members of the public should use DEET-containing insect repellents or other effective active ingredients properly to prevent mosquito bites, but the following precautions should be taken when using them:
 

• read the label instructions carefully first;
• apply right before entering an area with a risk of mosquito bites;
• apply on exposed skin and clothing;
• use DEET of up to 30 per cent for pregnant women and up to 10 per cent for children (for children who travel to countries or areas where mosquito-borne diseases are endemic or epidemic, and where exposure is likely, those aged 2 months or above can use DEET-containing insect repellents with a DEET concentration of up to 30 per cent);
• apply sunscreen first, then insect repellent;
• reapply only when needed and follow the instructions; and
• in addition to DEET, there are other insect repellents available on the market containing different active ingredients, such as IR3535 and picaridin. When using any insect repellent, the public should follow the usage instructions and precautions on the product label.

     ​The FEHD also appeals to members of the public to continue to stay alert and work together to carry out mosquito prevention and control measures early, including inspecting their homes and surroundings to remove potential breeding grounds, changing water in vases and scrubbing their inner surfaces, removing water in saucers under potted plants at least once a week, and properly disposing of containers such as empty cans and lunch boxes. The FEHD also advises members of the public and property management agencies to keep drains free of blockage and level all defective ground surfaces to prevent the accumulation of water. They should also scrub all drains and surface sewers with an alkaline detergent at least once a week to remove any mosquito eggs.
          
     The public should call 1823 in case of mosquito problems, and may visit the following pages for more information: the CF page of the CHP and the Travel Health Service, the latest Travel Health News, tips for using insect repellents, and the CHP Facebook Page, Instagram Account and YouTube Channel, and also the Mosquito Prevention and Control dedicated page of the FEHD.

Ends/Tuesday, April 21, 2026
Issued at HKT 19:38

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