China is battling its largest-ever outbreak of the Chikungunya virus, with over 10,000 cases reported nationwide. The city of Foshan is the worst hit, recording more than 7,000 infections. Experts say the virus has never been established in mainland China before, meaning most people have no immunity. “This suggests the population had no preexisting protection, making it easier for the virus to spread quickly,” said Oxford vaccine researcher Cesar Lopez-Camacho.

Spread by mosquito bites, Chikungunya causes fever, severe joint pain, and other flu-like symptoms. While rarely fatal, it can be dangerous for vulnerable people. Infected patients are being kept under mosquito nets in hospitals and must stay at least a week or test negative before leaving.

To control the outbreak, authorities are spraying insecticide, releasing mosquito-eating fish, and using drones to find and remove stagnant water. Locals face fines up to 10,000 yuan if they don’t clear standing water. Vice-Premier Liu Guozhong has ordered officials to “eliminate mosquitoes and cut off epidemic spread channels”.

Health experts urge anyone with symptoms to seek immediate testing and treatment to stop the virus from spreading further.