CHP investigates first imported chikungunya fever case in Hong Kong this year
*****************************************************************************
The case involved a 12-year-old boy with good past health living in Kwun Tong. He developed fever, rash and joint pain since July 31 and sought medical attention from a private doctor on the same day. Despite the symptoms are mild, he was referred to the Accident and Emergency Department of United Christian Hospital on August 1 due to his recent travel history. He was admitted for treatment in a mosquito-free environment on the same day. The patient is now in stable condition. His blood sample tested positive for CF virus upon laboratory testing.
Initial investigations revealed that the patient travelled to Foshan in Guangdong Province between July 17 and 30, and recalled a history of mosquito bites during the stay. Since the patient stayed in Foshan during the whole incubation period, the CHP considers that the patient was infected during travel, and the case was classified as an imported case. His household contacts (including one travel collateral) are currently asymptomatic and under medical surveillance. The CHP's epidemiological investigations is ongoing and has reported the case to the health authorities of Guangdong.
The Food and Environmental Hygiene Department (FEHD) has conducted 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.
The abovementioned case is the first imported CF case in Hong Kong this year. From 2016 to 2019, between one and 11 CF cases were recorded in Hong Kong each year, all of which were imported cases.
According to the World Health Organization, 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. Moreover, according to the information from the Foshan health authority, as of July 31 there were over 6 900 cases. The majority of cases (5 972 cases) were in Shunde District. All cases were mild, with no severe or fatal cases. As well, confirmed cases were also recorded in other cities in Guangdong Province recently. Regarding Macao, six imported cases and one local case of CF were recorded since mid-July.
"CF is not transmitted from person to person, and is primarily transmitted to humans through the bite of female Aedes mosquitoes carrying the CF virus. Eliminating mosquito breeding sites and avoiding mosquito bites are the most effective measures. During the early stage after the onset of symptoms (especially when a fever is present), the blood of patients of CF contains a large amount of virus, which is infectious to mosquitoes. If they are bitten by mosquitoes during the communicable period, further local transmission via mosquitoes is possible. Therefore, avoiding mosquito bites of the patient is an important measure to prevent local transmission," said the Head of the Communicable Disease Branch of the CHP, Dr Albert Au.
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.
Dr Au reminded members of the public that people returning from areas affected by mosquito-borne diseases should apply insect repellent for 14 days upon arrival in Hong Kong. Members of the public should closely observe personal health conditions, 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 arrange 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.
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.
Ends/Saturday, August 2, 2025
Issued at HKT 20:26
Issued at HKT 20:26
NNNN