CHP recorded one locally acquired case of chikungunya fever
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Latest case information
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The case involves a 59-year-old female living in Tung Chung. A preliminary investigation revealed that she developed a fever and joint pain on November 28. She attended the Accident and Emergency Department of North Lantau Hospital yesterday (November 30) and was admitted for treatment in a mosquito-free environment. She is currently in stable condition. Her blood sample tested positive for the chikungunya virus upon laboratory testing.
The preliminary investigation also revealed that the patient had no travel history during the incubation period. The case is classified as local. She is a staff of the Food and Environmental Hygiene Department (FEHD) who participated in a mosquito control operation near Tsing Yi Nature Trails on November 24 (within her incubation period). She reported being bitten by mosquitoes during the operation. Other than that, the CHP found no overlap between her activities during the incubation period and the locations visited by earlier confirmed cases. The CHP considered that the patient most likely contracted the infection through mosquito bites while working near Tsing Yi Nature Trails on that day, and that there is an epidemiological linkage between this case and the two recent local cases in Tsing Yi.
The patient participated in the mosquito control operation with approximately 40 staff near Tsing Yi Nature Trails on November 24. She has three household contacts. Currently, all individuals are asymptomatic. The CHP will provide them with medical surveillance and health advice. Laboratory testing will be arranged if necessary.
Hong Kong has recorded a total of 75 confirmed CF cases this year. Among them, seven were local cases, and the rest were imported cases.
Government's comprehensive follow-up actions
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Regarding the recent imported and local cases residing in Tsing Yi, the CHP initiated immediate epidemiological investigations upon notification and notified the FEHD of the patients' activity locations for mosquito control operations. As some confirmed cases have reportedly been bitten by mosquitoes while hiking along the Tsing Yi Nature Trails, the CHP considers the trails to be a higher-risk area. As a precautionary measure, since November 23, the CHP has urged individuals who have recently visited the Tsing Yi North area or hiked along the Tsing Yi Nature Trails to seek medical attention as soon as possible if they develop relevant symptoms and to call the CHP's enquiry hotline (2125 2373). The hotline operates daily from 9am to 8pm. The CHP received enquiries from two individuals with mild symptoms and has arranged blood tests for them. Both blood samples tested negative for the chikungunya virus.
Last week, the CHP also informed approximately 130 primary care doctors in Kwai Tsing District through the Primary Healthcare Commission, urging them to closely monitor whether their patients present with compatible symptoms and arrange blood tests for those concerned. The CHP's Public Health Laboratory Services Branch will provide free testing services. All relevant government departments have strengthened mosquito vector control measures for all imported cases and conducted active case tracing in the district. The CHP's epidemiological investigation is ongoing.
Specifically targeting confirmed cases who visited the Tsing Yi Nature Trails or the surrounding area, the FEHD has been conducting intensive fogging operations to eliminate adult mosquitoes along the hiking trails. At suitable locations, large ultra-low volume foggers have been deployed, and robot dog is being put on trial to enhance operational effectiveness. The FEHD has also set up new mosquito trapping devices, cleared discarded containers and garbage that could bring stagnant water, and applied larvicide oil or larvicides in areas with stagnant water that cannot be removed immediately. Pamphlets have been also distributed to hikers in the area, urging citizens to be vigilant against mosquito infestations. The FEHD has earlier requested the relevant departments to strengthen efforts in eliminating potential mosquito breeding sites along the Tsing Yi Nature Trails. The FEHD also held meetings of the inter-departmental task forces on anti-mosquito work across districts, to discuss the latest developments regarding the situation and plan accordingly to coordinate relevant departments and stakeholders in strengthening mosquito prevention and control measures in areas under their purview.
Furthermore, the 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 cases, 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 to be 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/Monday, December 1, 2025
Issued at HKT 21:09
Issued at HKT 21:09
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