The Centre for Health Protection (CHP) of the Department of Health (DH) today (August 6) announced that three new cases of chikungunya fever (CF) had been recorded, all of which were imported cases, as at 5pm today. The CHP will continue to strengthen its surveillance work in view of the recent CF cases. The CHP reminded members of the public to maintain strict environmental hygiene, mosquito control and personal protective measures both locally and when travelling outside Hong Kong. Avoiding mosquito bites and eliminating mosquito breeding sites are effective ways to prevent CF.

     The first case involves a 79-year-old female with good past health living in Southern District. Initial investigations revealed that the patient travelled to Foshan in Guangdong Province to visit relatives between July 1 and 31, and did not recall any history of mosquito bites during the stay. She developed fever and joint pain since August 4. She attended the Accident and Emergency Department of Queen Mary Hospital yesterday (August 5) and was admitted for treatment in a mosquito-free environment on the same day. The patient is now in stable condition. Her blood sample tested positive for CF virus upon laboratory testing.

     Since the patient stayed in Foshan during most of the incubation period, the CHP considered that the patient was infected during travel, and the case was classified as an imported case. She has no travel collaterals nor household contacts. The CHP's epidemiological investigations is ongoing and has reported the case to the health authorities of Guangdong.

     The second and third case involve a 55-year-old man with underlying illnesses and his 10-year-old son with good past health. They live in Kwai Tsing District. Initial investigations revealed that both patients travelled to Bangladesh between July 12 and August 3, and arrived Hong Kong on August 3. The boy recalled a history of mosquito bites during the stay while his father did not recall any history of mosquito bites. The 55-year-old man developed fever and joint pain in Bangladesh since July 27. After returning to Hong Kong, he sought medical attention at Tsing Yi Cheung Hong General Out-patient Clinic on August 4 and was referred to Accident and Emergency Department of Princess Margaret Hospital. He was admitted to Princess Margaret Hospital for treatment in a mosquito-free environment on the same day. The boy developed similar symptoms in Bangladesh since August 1. He sought medical attention at the Hong Kong Adventist Hospital - Tsuen Wan on the day returning to Hong Kong and was admitted. He was transferred to Princess Margaret Hospital yesterday for treatment in a mosquito-free environment. Both patients are now in stable condition. Their blood samples tested positive for CF virus upon laboratory testing.

     Since they stayed in Bangladesh during the whole incubation period, the CHP considered that both patients were infected during travel, and the cases were classified as imported cases. The patient's two household contacts, who are also their travel collaterals, are currently asymptomatic and under medical surveillance. The CHP's epidemiological investigations is ongoing and has reported the cases to the health authority of Bangladesh.

     The Food and Environmental Hygiene Department (FEHD) is conducting vector investigations and targeted mosquito control operations and will intensify mosquito prevention and control measures at the residence of the patient, as well as locations visited after the onset of symptoms. These measures include:
 

• carrying out intensive fogging in the scrubby areas within 250-metre radius of the relevant locations to kill adult mosquitoes;
• carrying out inspection 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.

     A total of four CF cases have been recorded in Hong Kong this year, all of which were imported cases. From 2016 to 2019, between one and 11 CF cases were recorded in Hong Kong each year, all of which were imported cases.

     The Head of the Communicable Disease Branch of the CHP, Dr Albert Au, reminded members of the public to adopt precautions in the rainy season against mosquito-borne diseases. If members of the public return from areas affected by mosquito-borne diseases, they should apply insect repellent for 14 days upon arrival in Hong Kong. They should closely observe their personal health condition, in particular symptoms such as fever, joint pain and rash. If they feel unwell, they should seek medical advice promptly and provide their travel details to the doctor for clinical diagnosis and arrangement of appropriate testing based on an individual patient's condition. Members of the public are urged not to self-medicate, particularly with aspirin or non-steroidal anti-inflammatory drugs (such as ibuprofen), as these drugs may cause serious side effects, for example increasing the risk of haemorrhage. In general, children should not take medications containing aspirin to relieve fever or other symptoms, as it may lead to a serious and potentially fatal complication called "Reye's syndrome".

     Despite severe or fatal cases caused by CF is rare and the symptoms are milder than that of Dengue Fever, and most patients recover on their own, as local mosquitoes have not carried the CF virus, the Government strives to prevent CF from becoming endemic in Hong Kong, and has adopted multi-pronged emergency preparedness, including strengthening public education and publicity, stepping up control measures at boundary control points, enhancing local testing capabilities, arranging mosquito-free environment for treatments, conducting epidemiological investigations and risk assessments for confirmed cases, intensifying mosquito prevention and control measures, etc. The Public Health Laboratory Services Branch of the CHP is equipped with sufficient testing capabilities. The CHP has, in collaboration with the Hospital Authority, further enhanced the local testing capabilities to ensure that in the event of an outbreak, suspected cases could be tested as soon as possible with an aim of early detection and diagnosis.
      
     The FEHD 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. 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;
• Install mosquito screens on windows and doors if necessary, or use mosquito screens or nets in indoor areas;
• 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.

     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 Mosquito Prevention and Control dedicated page of the FEHD.

Ends/Wednesday, August 6, 2025
Issued at HKT 20:50

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