Update on chikungunya fever
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Analysis of imported cases
"Hong Kong has recorded nine imported CF cases this year, involving six males and three females aged between 8 and 79 years (median age: 31). Five cases involved individuals who had travelled to Foshan in Guangdong Province during the incubation period, while four involved individuals who had travelled to Bangladesh. The public should be aware that although the number of new CF cases in Foshan in Guangdong Province has been declining steadily in the past few weeks, many countries worldwide are currently experiencing CF outbreaks. It is essential to check the situation of the destinations before travelling abroad. Members of the public who experience typical symptoms of CF (e.g. fever and joint pain) after returning to Hong Kong from a region where CF is prevalent should seek medical attention immediately and inform their doctors of their travel history. The public should not self-medicate, with non-steroidal anti-inflammatory drugs (such as ibuprofen), to prevent aggravating the risk of haemorrhage. In general, children should not take medications containing aspirin to relieve fever or other symptoms because it may lead to Reye's syndrome, a serious and potentially fatal complication," the Controller of the CHP, Dr Edwin Tsui said.
"The CHP's genetic analysis showed that Aedes albopictus mosquitoes can effectively transmit the currently circulating CF virus. If imported cases are bitten by mosquitoes during the infectious period in Hong Kong, there is a risk of local transmission. Therefore, mosquito prevention and control efforts are of the utmost importance. Whether in town or travelling abroad, it is important to maintain environmental hygiene, take mosquito prevention and control measures, and adopt personal protective measures. Scientific research indicates that asymptomatic or pre-symptomatic infected individuals can transmit the CF virus to mosquitoes through bites. Residents returning to Hong Kong from areas affected by mosquito-borne diseases should continue to take measures to prevent mosquito bites for 14 days," he added.
Continuously strengthening prevention and control
The Food and Environmental Hygiene Department (FEHD) continues to conduct vector investigations and targeted mosquito control operations and has intensified mosquito prevention and control measures at the residence of the patients, as well as locations visited after the onset of symptoms. These measures include:
- carrying out intensive fogging in the scrubby areas within a 250-metre radius of the relevant locations to kill adult mosquitoes;
- carrying out inspection of the locations, removing stagnant water, applying insecticides and disposing of abandoned water containers every week with a view to preventing mosquito breeding; and
- enhancing public education efforts through organising health talks, setting up mobile education stations, and distributing publicity leaflets.
The CHP's Port Health Division continues to step up inspections at boundary control points and to remind cross-boundary public transport operators and other relevant parties to ensure good environmental hygiene and effective implementation of anti-mosquito measures. Furthermore, staff members of the Port Health Division distribute leaflets to travellers, conduct temperature screenings for inbound travellers, conduct health assessments for travellers with fever or related symptoms, and refer them to hospitals for follow-ups when necessary.
To raise awareness among the elderly about preventing mosquito-borne diseases, the Visiting Health Teams under the Elderly Health Service of the DH have been advising the elderly on mosquito-borne diseases prevention and tips on travel health at health talks conducted at District Elderly Community Centres and Neighbourhood Elderly Centres. Besides, the Visiting Health Teams have also reminded all residential care homes for the elderly in Hong Kong to enhance mosquito control measures. The DH's Maternal and Child Health Centres, Student Health Service Centres and Special Assessment Centres also advise pregnant women, infant carers and students on symptoms and preventive measures of the mosquito-borne diseases.
To strengthen support for ethnic minority communities, essential information on CF has also been translated into 10 ethnic minority languages (namely Hindi, Nepali, Urdu, Thai, Bahasa Indonesia, Tagalog, Vietnamese, Punjabi, Sinhala and Bengali) and uploaded to the CHP website.
Dr Edwin Tsui reminded members of the public to adopt precautions during the rainy season against mosquito-borne diseases. Proper use of DEET-containing insect repellents or other effective active ingredients can 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.
In addition, the FEHD 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 soft drink cans and lunch boxes. The FEHD also advises members of the public and estate management bodies 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/Saturday, August 23, 2025
Issued at HKT 17:30
Issued at HKT 17:30
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