Update on mosquito-borne diseases, dengue fever and chikungunya fever
The Centre for Health Protection (CHP) of the Department of Health today (May 29) announced the latest situation regarding dengue fever (DF) and chikungunya fever (CF). As temperatures rise and the humidity increases, creating favourable conditions for mosquito breeding, members of the public are reminded to 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.
Dengue fever
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From May 22 to yesterday (May 28), the CHP recorded one imported DF case. The patient had travelled to Singapore and Malaysia during the incubation period.
Hong Kong has recorded 20 DF cases so far this year, including 19 imported cases and one local case. A total of 59 DF cases were recorded last year (2025), all of which were imported cases. In 2024, 161 DF cases were recorded, including 156 imported cases 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 4 million cases and over 3 000 DF-related deaths were reported in 97 countries/territories.
DF is prevalent in many neighbouring tourist destinations. In 2025, Indonesia, India and Vietnam each recorded over 120 000 cases; Malaysia and Thailand each recorded over 50 000 cases; and Singapore recorded over 4 000 cases. Meanwhile, as of May 10, the Guangdong Provincial Center for Disease Control and Prevention recorded 97 cases in Guangdong Province this year, including eight locally infected cases. Guangdong Province recorded over 3 500 locally infected cases in 2025.
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.
Chikungunya fever
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From May 22 to yesterday, no new cases of CF had been recorded. Hong Kong has recorded two confirmed CF cases so far this year, both of which were imported cases. Hong Kong recorded a total of 82 confirmed CF cases last year. Among them, 11 were local cases and the rest were imported cases.
Last year, a total of 502 264 CF cases and 186 CF-related deaths have been reported in 41 countries/territories. Cases have been reported in the Americas, Africa, Asia, and Europe. Meanwhile, as of May 10, the Guangdong Provincial Center for Disease Control and Prevention recorded four cases in Guangdong Province this year, including one locally infected case.
Preventive measures to be taken by the public
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According to the Food and Environmental Hygiene Department (FEHD), the average temperature and rainfall recorded in April this year were higher than those in the same period last year, creating favourable conditions for mosquito growth and breeding. As a result, the rise in gravidtrap indexes occurred earlier this year.With the increase in rainfall in May, the gravidtrap indexes are expected to rise further.
Therefore, the CHP reminded members of the public to maintain good environmental hygiene, and to 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. Mosquito-borne diseases such as DF and CF are endemic in various countries worldwide. The risk of importation persists. Members of the public should check the situation at their destinations before travelling abroad, especially when travelling to Southeast Asian countries. Additionally, whether travelling or not, 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.
The Centre for Health Protection (CHP), Photo source: reference image
