Update on mosquito-borne diseases, dengue fever and chikungunya fever
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Dengue fever
From July 11 to yesterday (July 17), the CHP recorded one imported DF case. The patient had travelled to the Philippines during the incubation period.
As of yesterday, 30 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. In 2023, 62 imported cases of DF were recorded.
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 2023, over 6.5 million cases and more than 7 300 dengue-related deaths were reported in over 80 countries/territories. In 2024, the WHO recorded over 14 million cases, which was a record number.
DF is prevalent in many neighbouring tourist destinations. Indonesia, Malaysia, Thailand and Vietnam have each recorded over 15 000 cases so far this year. Singapore also recorded over 2 800 cases. Meanwhile, according to the Guangdong Provincial Center for Disease Control and Prevention, Guangdong Province has recorded a total of 140 locally infected cases so far this year. A total of 51 cases were recorded in a week between July 7 and 13, with the highest number of cases recorded in Guangzhou, Zhongshan, Foshan and Chaozhou.
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 website.
Chikungunya fever
There have been no CF cases in Hong Kong since 2020.
According to the WHO, CF cases have been recorded in more than 110 countries/regions. As of early June this year, over 220 000 cases had been reported in 14 countries/regions worldwide (including the Mainland, Taiwan and Singapore which are popular tourist destinations for Hong Kong citizens). Of these cases, about 80 were fatal. Furthermore, according to the Guangdong Provincial Center for Disease Control and Prevention, Guangdong Province has recorded a total of 481 locally infected cases in a week between July 8 and 14, and all cases were reported from Foshan (478 in Shunde and three in Chancheng).
"There are frequent imported cases of dengue fever in Hong Kong, as well as occasional sporadic local cases every year. The presence of Aedes albopictus in Hong Kong makes our population vulnerable. Regarding CF, though Aedes aegypti, the primary vector for spreading CF, is not found in Hong Kong, Aedes albopictus can also transmit CF. Imported cases of CF and DF can lead to local transmission if they are bitten by mosquitoes during the communicable period. Mosquitoes breed quickly during the hot, rainy spring and summer months. There are risks of mosquito-borne diseases outbreaks if mosquito control is inadequate. Hence, mosquito control is of paramount importance. Members of the public are advised to maintain strict environmental hygiene, mosquito control and personal protective measures both locally and when travelling outside Hong Kong. The public is reminded that eliminating mosquito breeding sites and avoiding mosquito bites are key to preventing mosquito-borne diseases. Those returning from areas affected by mosquito-borne diseases should apply insect repellent for 14 days upon arrival in Hong Kong. If feeling unwell, they should seek medical advice promptly and provide their travel details to a doctor," Dr Tsui added.
Members of the public are also reminded to take heed of the following advice on mosquito control:
- Thoroughly check all gully traps, roof gutters, surface channels and drains to prevent blockage;
- Scrub and clean drains and surface channels with an alkaline detergent compound at least once a week to remove any deposited mosquito eggs;
- Properly dispose of refuse, such as soft drink cans, empty bottles and boxes, in covered litter containers;
- Completely change the water of flowers and plants at least once a week. The use of saucers should be avoided if possible;
- Level irregular ground surfaces before the rainy season;
- Avoid staying in shrubby areas; and
- Take personal protective measures such as wearing light-coloured long-sleeved clothes and trousers, and apply insect repellent containing DEET to clothing or uncovered areas of the body when doing outdoor activities.
DEET-containing insect repellents are effective and the public should take heed of the tips below:
- Read the label instructions carefully first;
- Apply right before entering an area with 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*;
- Apply sunscreen first, then insect repellent; and
- Reapply only when needed and follow the instructions.
The public should call 1823 in case of mosquito problems and may visit the following pages for more information: the DF page of the CHP and the Travel Health Service, the chikungunya fever page of the CHP and the Travel Health Service, the latest Travel Health News, tips for using insect repellents, and the CHP Facebook Page and YouTube Channel.
Ends/Friday, July 18, 2025
Issued at HKT 17:05
Issued at HKT 17:05
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