Hong Kong health authorities recently confirmed a new locally acquired case of Chikungunya fever, raising concerns about community transmission after a Food and Environmental Hygiene Department (FEHD) worker tested positive for the mosquito-borne virus. On Sunday, Dec. 1, the Department of Health’s Centre for Health Protection (CHP) announced the diagnosis involving a 59-year-old woman residing in Yu Tung Court, Tung Chung, who presented with symptoms consistent with the infection.
The patient, whose condition is currently stable, sought medical attention after developing fever and enduring joint pain starting Nov. 28. She was subsequently admitted to North Lantau Hospital where laboratory results confirmed the presence of the Chikungunya virus in her blood sample. Critically, investigations revealed the woman had no recent travel history outside of Hong Kong during the exposure period, classifying this as the seventh local case this year.
Investigating the Exposure Point
Health officials are tracing the source of the infection, focusing on her professional activities. The patient, an FEHD staff member, participated in a mosquito control operation near the Tsing Yi Nature Trails on Nov. 24. She reported being bitten by mosquitoes while working at that location.
The CHP determined that this site is the most probable point of infection. While the patient’s movements did not otherwise overlap with recently confirmed cases, this new diagnosis is considered epidemiologically linked to two other recent local infections associated with the Tsing Yi area. This suggests an active transmission cycle is ongoing within specific local environments.
During the control exercise on Nov. 24, approximately 40 FEHD colleagues worked alongside the patient. All three of her household contacts and the participating staff members are currently asymptomatic. As a precautionary measure, the CHP is placing these close contacts under medical surveillance, providing health guidance, and arranging for laboratory testing if necessary.
Mitigation and Public Health Context
Chikungunya fever, characterized by severe joint pain, fever, and muscle aches, is transmitted to humans through the bite of infected Aedes mosquitoes, specifically Aedes aegypti and Aedes albopictus, which are common in Hong Kong. While rarely fatal, the disease can cause debilitating symptoms that persist for weeks or months.
This latest case underscores the ongoing public health challenge posed by mosquito-borne diseases in densely populated areas. The CHP has reported a total of 75 confirmed Chikungunya cases across Hong Kong this year; however, the seven local cases are particularly worrying as they indicate indigenous transmission.
Protecting Against Mosquito-Borne Illnesses
Residents, particularly those working outdoors or near known breeding sites, are urged to enhance personal protection measures. The CHP recommends several actionable steps to reduce transmission risk:
- Eliminate Standing Water: Regularly check and remove stagnant water sources around homes and workplaces, as these are primary mosquito breeding grounds.
- Use Repellent: Apply insect repellent containing DEET, picaridin, or IR3535 when spending time outdoors, especially during dawn and dusk.
- Install Screens: Ensure doors and windows are fitted with fine-mesh screens to keep mosquitoes out.
- Report Infestations: Promptly report persistent mosquito issues in public areas to the relevant authorities.
The vigilance of both health professionals and the public is essential to contain further local spread and manage the risk associated with vector-borne diseases as Hong Kong moves into the winter months. Health experts advise residents to remain alert for symptoms and seek medical advice immediately if they suspect infection.