Thousands of cases of chikungunya virus have been reported in Foshan, Guangdong, with infections also appearing in nearby cities.
The virus is transmitted through the bite of an infected mosquito and warming climates are helping the insect spread. It causes fever along with severe joint pain, which can sometimes persist for years, though it is rarely fatal.
The current global surge of cases began in early 2025 on Indian Ocean islands, says the World Health Organization (WHO). It has since reached Africa, South Asia, Southeast Asia, parts of Europe, and China. WHO says if urgent action is not taken the outbreak could mirror the massive 2004-2005 epidemic.
The chikungunya virus, which was first identified in Tanzania in the 1950s, is transmitted primarily by the Aedes aegypti mosquito, Professor Cheng Gong of Tsinghua University told The Paper. A viral mutation in 2007 allowed Aedes albopictus, or the Asian tiger mosquito, to carry the virus efficiently, bringing it into subtropical and temperate zones. Cheng said the species now thrives in northern China, Europe and the United States.
Warming climates encourage the mosquito to spread, Cheng noted. “In China, its range is expanding northward, now reaching northern provinces such as Shandong, Henan, and Liaoning,” he said.
Unfortunately, mosquitoes are not China’s only temperature-related health issue, as highlighted Chinese scientists in new research published in Nature this year. The study projects that, without adaptation and under a high-emission scenario, extreme heat could cause over 5.1 million additional hospitalisations annually in China by 2100. Southern and south-western regions may face the heaviest burdens.
The study also finds that temperature extremes already strain health systems unevenly. Less-developed regions bear higher relative burdens despite having fewer medical resources. Under high-emission pathways, the economic cost of heat-related hospitalisations could reach USD 5.2 billion a year by the end of the century.
Read Dialogue Earth’s previous analysis piece on climate change and health.