The Centre for Health Protection (CHP) in Hong Kong is intensifying mosquito control and epidemiological surveillance following a significant spike in Chikungunya fever (CF) cases this year, including four locally acquired infections. As of November 25, 2025, the city documented 71 confirmed CF cases, with the vast majority imported. The investigation is currently focused on an alleged cluster of imported infections in Tsing Yi, coupled with global data that reveals a concerning rise in the mosquito-borne illness worldwide.
Global and Local Case Overview
Globally, the scale of CF transmission remains substantial. From the beginning of 2025 through September 30, international health authorities reported 445,271 suspected and confirmed cases, alongside 155 fatalities attributed to the virus, across 40 nations in the Americas, Africa, Asia, and Europe. This continued international activity underscores the necessity for travelers to meticulously review destination health advisories before departure.
In Hong Kong, while the number of new cases held steady on November 25, the focus has shifted to localized prevention. The public health alert was particularly raised by an alleged cluster of five recent imported cases residing in Tsing Yi. Epidemiological tracing by the CHP suggests these individuals—who share residences—had overlapping activities in the Tsing Yi North area, specifically around Tsing Yi Town Centre and the adjacent Tsing Yi Nature Trails, during their incubation and infectious phases.
Targeted Response in Tsing Yi
In response to the potential localized risk, the CHP has initiated several public health interventions. The Food and Environmental Hygiene Department (FEHD) has been directed to conduct immediate and targeted vector control, focusing specifically on mosquito breeding grounds within the designated high-risk zones, particularly along the Tsing Yi Nature Trails.
The trail areas were highlighted as higher risk after some confirmed patients recalled receiving mosquito bites while hiking. To confirm potential transmission linkages, the CHP is conducting detailed genomic sequencing and analysis of patient samples. This process compares the viral structure of local and imported infections to determine if any cross-transmission occurred within Hong Kong.
Actionable Advice for Residents and Tourists
Given the potential for local transmission, the CHP strongly advises individuals who have visited the Tsing Yi Nature Trails or surrounding areas since November 1 to remain vigilant for symptoms. Chikungunya symptoms typically include abrupt onset of fever and severe joint pain, though milder symptoms may occur.
Prompt Medical Attention Crucial:
Anyone experiencing compatible symptoms (fever, severe joint pain, headache, muscle pain, joint swelling, or rash) should seek immediate medical consultation. They are also urged to contact the CHP-dedicated inquiry hotline (2125 2373), which operates daily between 9 a.m. and 8 p.m. to facilitate timely investigation and contact tracing.
Travelers are reminded that the best defense against this viral illness is personal prevention. Since the Aedes mosquito species transmits Chikungunya, travelers and residents should apply insect repellent, wear long sleeves and pants outdoors, and eliminate stagnant water sources near residences to discourage mosquito breeding.
While the epidemiological investigation remains active, continued community cooperation and reporting are vital to swiftly identifying and containing any further localized transmission chains. The current situation highlights the persistent threat of imported infectious diseases and the critical necessity of robust local vector control measures.