Update on chikungunya fever
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Latest case information
The first case involves a 10-year-old boy living in Sha Tin District. An initial investigation revealed that he travelled to Foshan, Guangdong Province, on August 16. During his stay, he was bitten by mosquitoes. He returned to Hong Kong on August 20 and developed a fever, a rash and joint pain on August 24. He attended the Accident and Emergency Department of Prince of Wales Hospital yesterday (August 25) and was admitted for treatment in a mosquito-free environment. He is now in stable condition. His blood sample tested positive for the CF virus upon laboratory testing. His three household contacts, including a person who travelled to Foshan with the boy, are currently asymptomatic and under medical surveillance.
Another case involves a 31-year-old female living in Sham Shui Po District. An initial investigation revealed that she travelled to Indonesia from August 8 to 23. During her stay, she was bitten by mosquitoes. She developed a fever on August 23, and when she returned to Hong Kong on the next day (August 24), she developed joint pain. She attended the Accident and Emergency Department of Princess Margaret Hospital yesterday and was admitted for treatment in a mosquito-free environment. She is now in stable condition. Her blood sample tested positive for the CF virus upon laboratory testing. Her four household contacts are currently asymptomatic and under medical surveillance.
Since the two patients stayed in Foshan and Indonesia respectively during their incubation periods, the CHP considered that they were infected during travels. Both cases were classified as imported. The CHP's epidemiological investigations are ongoing and it has reported the cases to the health authorities of Guangdong Province and Indonesia respectively.
So far this year, Hong Kong has recorded a total of 11 confirmed CF cases. All are imported cases. From 2016 to 2019, Hong Kong recorded between one and 11 imported cases annually.
"According to information from the Guangdong Provincial Disease Control and Prevention Administration, there were 336 new CF cases in Guangdong in the past week (August 17 to 23), a significant decrease compared to the previous two weeks, which reported 1 387 cases (August 3 to 9) and 830 cases (August 10 to 16) respectively. All cases were mild, with no severe or fatal cases reported. However, we must remain vigilant and continue to adopt a multipronged approach to prevent local transmissions. As the new school year is about to begin, the CHP yesterday issued a letter to schools again, urging them to follow the Food and Environmental Hygiene Department (FEHD)'s anti-mosquito guidelines to strengthen efforts to clear stagnant water on school premises and eliminate mosquito breeding sites. They should also remind the staff members and students to enact mosquito prevention and personal protective measures to prevent the spread of mosquito-borne diseases on campus," the Controller of the CHP, Dr Edwin Tsui said.
Continuously strengthening prevention and control
The FEHD continues to conduct vector investigations and targeted mosquito control operations and intensify mosquito prevention and control measures at the residences of patients, as well as at locations visited after the onset of symptoms. These measures include:
- carrying out intensive fogging in scrubby areas within a 250-metre radius of the relevant locations to kill adult mosquitoes;
- carrying out inspections 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.
Additionally, 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 them on mosquito-borne disease prevention and tips on travel health at health talks conducted at District Elderly Community Centres and Neighbourhood Elderly Centres. Moreover, 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 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 Tsui reminded members of the public that they must take proper mosquito control and personal protective measures both locally and during travel. Individuals experiencing relevant symptoms should seek medical advice promptly and inform their doctors if they have a travel history. 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.
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 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/Tuesday, August 26, 2025
Issued at HKT 20:04
Issued at HKT 20:04
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