Chikungunya in Hong Kong: A Second Locally Acquired Case

Hong Kong health officials have confirmed a second locally acquired case of chikungunya on November 1, 2024. This growth raises concerns about potential local transmission of the mosquito-borne virus, prompting increased surveillance and public health measures.

What is chikungunya?

Chikungunya is a viral disease transmitted to humans through the bite of infected Aedes mosquitoes, primarily Aedes aegypti and Aedes albopictus. these mosquitoes are also known to transmit dengue and Zika viruses. The name “chikungunya” originates from an African word meaning “to become bent over,” referring to the debilitating joint pain often associated with the illness.

Symptoms of Chikungunya

Symptoms typically appear 3-7 days after the mosquito bite. Common symptoms include:

• High fever
• severe joint pain (frequently enough in the limbs)
• Muscle pain
• Headache
• Rash
• Fatigue

While the fever usually subsides within a few days, joint pain can persist for weeks, months, or even years in certain specific cases. Severe cases can lead to complications, though fatalities are rare.

The Recent Cases in Hong Kong

The first locally acquired case in Hong Kong in over a decade was reported in September 2024. The latest case involves a 55-year-old woman with no recent travel history to areas known to have chikungunya transmission. Genome sequencing of the virus from both cases has confirmed they are linked, indicating local circulation. The Centre for Health protection (CHP) is actively investigating the source of infection and potential mosquito breeding sites.

Inquiry and Response

The CHP is undertaking the following measures:

• Enhanced surveillance for chikungunya cases
• Mosquito surveillance and control measures in affected areas
• Public health education to raise awareness about chikungunya and mosquito bite prevention
• Contact tracing to identify potential additional cases

Prevention of Chikungunya

The most effective way to prevent chikungunya is to avoid mosquito bites. Key preventative measures include:

• Use insect repellent: Apply repellent containing DEET, picaridin, or IR3535 to exposed skin and clothing.
• Wear protective clothing: Cover up with long sleeves, long pants, and socks when outdoors.
• Eliminate mosquito breeding sites: Remove standing water from containers such as flower pots, tires, and buckets.
• Use mosquito nets: Sleep under mosquito nets, especially if you are not in an air-conditioned room.
• Install window and door screens: Ensure screens are intact and properly fitted.

Global Distribution and Risk

Chikungunya is prevalent in Africa, Asia, Europe, and the Americas.Outbreaks have occurred in various countries, including India, Thailand, the Caribbean, and South America. The risk of chikungunya is highest during the rainy season when mosquito populations are abundant.Climate change and increased international travel contribute to the spread of the virus to new areas.

Key Takeaways

• Chikungunya is a mosquito-borne viral disease causing fever and severe joint pain.
• hong Kong has confirmed two locally acquired cases in recent months,indicating potential local transmission.
• Prevention focuses on avoiding mosquito bites and eliminating breeding sites.
• The CHP is actively investigating and implementing control measures.

The confirmation of a second locally acquired case underscores the importance of vigilance and proactive mosquito control measures in Hong Kong. Continued surveillance and public awareness campaigns are crucial to prevent further spread and protect public health. The situation will be closely monitored to assess the extent of local transmission and adjust public health strategies accordingly.