Update on mosquito-borne diseases, chikungunya fever and dengue fever
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Chikungunya fever
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As of 5pm today, two new imported CF cases have been recorded.
The first case involves a 53-year-old female living in Kwai Tsing District. Initial investigation revealed that she visited Zhongshan in Guangdong between November 2 and 4. She developed joint pain and rash on November 19, followed by a fever yesterday (November 20). She sought medical attention at the Accident and Emergency Department of Princess Margaret Hospital on the same day.
The second case involves a 60-year-old female living in Kwai Tsing District. Initial investigation revealed that she visited Shenzhen in Guangdong on November 17. She developed joint pain on November 19, followed by rash on the following day (November 20). She sought medical attention at the Accident and Emergency Department of Yan Chai Hospital on the same day.
Both patients have been admitted for treatment in a mosquito-free environment. They are now in stable condition. Their blood sample tested positive for the chikungunya virus upon laboratory testing.
The 53-year-old patient has three household contacts, and five travel collaterals to Zhongshan, who are currently asymptomatic. The 60-year-old patient has two household contacts who travelled with her to Shenzhen. One of them developed mild joint pain. The CHP has referred the person concerned to the Accident and Emergency Department to undergo examination and blood test. All of the abovementioned individuals are under medical surveillance.
As both patients have travelled to CF-affected areas about two weeks prior to symptom onset, the CHP preliminarily considered that both cases were infected during their travel. These cases are classified as imported. The CHP will report the cases to the health authority of Guangdong Province. The CHP's epidemiological investigations are in progress.
Furthermore, in light of the local case involving a 68-year-old female who lives in Tung Hei Court in Shau Kei Wan, the CHP urged the residents living in the vicinity of the patient's residence to seek medical advice or contact the CHP immediately if they presented with a fever, rash or joint pain since October 15. The CHP collaborated with the Eastern District Services & Community Care Teams to distribute leaflets on CF prevention and questionnaire surveys to about 3 000 households in the affected areas in the vicinity of Tung Hei Court to remind residents to monitor for relevant symptoms and maintain good environmental hygiene at home.
As of 5pm today, the CHP has conducted assessments for over 4 950 individuals through the health consultation booth on 2/F, Hing Tung Shopping Centre in Shau Kei Wan, its inquiry hotline, questionnaire surveys and door-to-door visits at Tung Hei Court. No new symptomatic persons have been identified in the past six days. Four individuals with mild symptoms previously have been arranged to undergo blood tests, and all tested negative for the chikungunya virus. Since the health consultation booth has only sporadic visits recently and all individuals who underwent blood tests have returned negative results, the booth will cease operation starting tomorrow. The enquiry hotline (2125 2373) will continue to operate daily from 9am to 6pm.
Hong Kong has recorded a total of 67 confirmed CF cases this year. Among them, four were local cases, and the rest were imported cases.
Dengue fever
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From November 14 to yesterday (November 20), the CHP recorded one imported DF case. The patient had travelled to India during the incubation period.
As of yesterday, 54 imported DF cases have been recorded so far this year. A total of 161 cases of DF were recorded in 2024, including 156 imported and five local cases.
According to the World Health Organization (WHO), the global incidence of DF has markedly increased over the past two decades, posing a substantial public health challenge. In 2024, the WHO recorded over 14 million cases, which was a record number. From January to July 2025, over four million cases and over 3 000 DF-related deaths have been reported in 97 countries/territories.
DF is prevalent in many neighbouring tourist destinations. Indonesia, India and Vietnam have each recorded over 90 000 cases so far this year; Malaysia and Thailand have each recorded over 40 000 cases; and Singapore has also recorded over 3 500 cases. Meanwhile, according to the Guangdong Provincial Center for Disease Control and Prevention, Guangdong Province has recorded 3 339 locally infected cases so far this year. A total of 130 cases were recorded in a week between November 3 and 9, with the highest number of cases recorded in Chaozhou, Shenzhen, Shantou, Guangzhou and Foshan.
Detailed information on the latest DF situation in Hong Kong, as well as neighbouring and overseas countries and areas, has been uploaded to the CHP's website.
Continuously strengthening prevention and control
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The Food and Environmental Hygiene Department (FEHD) and relevant departments have comprehensively enhanced the mosquito control operations in Hong Kong since July this year, and this has continued. Among these, the FEHD has conducted vector investigations and targeted mosquito control operations against the imported and local cases. In light of the local case, the FEHD has immediately conducted follow-up actions, including:
- 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.
The abovementioned measures will be continued. Furthermore, the Government will further enhance the mosquito control efforts in addition to the existing measures.
Preventive measures 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/Friday, November 21, 2025
Issued at HKT 22:50
Issued at HKT 22:50
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