China's Chikungunya Outbreak Related to the East/Central/South African Virus Genotype

The U.S. Centers for Disease Control and Prevention (CDC) has reissued a Level 2 travel notice, advising travelers to practice enhanced precautions due to the ongoing Chikungunya fever outbreak in Guangdong Province, Republic of China.

Since July 2025, this mosquito-transmitted virus has been challenging China's public health systems on the mainland,

And in Hong Kong, where over 10 local Chikungunya cases have been reported, the popular hiking area, Tsing Yi Nature Trails, was recently closed.

These outbreaks highlight the need to improve surveillance of viral mutations.

According to China CDC Weekly (7(49): 1528-1532), the circulating strain of the Chikungunya virus in Foshan, Guangdong, belongs to the East/Central/South African genotype, not the Indian Ocean Lineage. However, the specific mutations in the viral genome remained unclear.

China's CDC wrote that these mutations are known to enhance viral replication and virus transmission efficiency in Aedes albopictus mosquitoes. 

On December 17, 2025, the U.S. CDC stated that we can protect ourselves from this disease by preventing mosquito bites and that vaccination is recommended for travelers visiting an area with a chikungunya outbreak.  

The CDC also advises pregnant women to reconsider travel to these affected areas.

If you do visit these areas of China, seek medical care immediately if you develop fever, joint pain, headache, muscle pain, joint swelling, or rash during or after travel.