A mosquito-borne virus that can leave infected people debilitated for years is spreading to more regions of the world, as climate change creates new habitats for the insects that carry it.

More than 240,000 cases of the virus, chikungunya, have been reported around the world so far this year, including 200,000 cases in Latin America and 8,000 in China, the first cases ever reported there. Chinese authorities have launched an urgent effort to try to stifle the virus with public health measures that evoke the response to Covid-19.

Chikungunya is not circulating in the United States or Canada, but cases have been reported in France and Italy. The disease is endemic in Mexico.

The World Health Organization is warning that current transmission patterns resemble a global outbreak that infected 500,000 people 20 years ago, contributing to a surge of new disabilities.

Although it is rarely fatal, chikungunya causes excruciating and prolonged joint pain and weakness.

“You have people who were working, with no disabilities, and from one day to the next, they cannot even type on a phone, they can’t hold a pen, a woman cannot even hold a knife to be able to cook for her family,” said Dr. Diana Rojas Alvarez, who leads chikungunya work at the W.H.O. “It really impacts quality of life and also the economy of the country.”

What is chikungunya, and how dangerous is it?

Chikungunya is a virus from the same family as Zika and dengue fever. Two different species of mosquitoes, Aedes aegypti and Aedes albopictus, transmit chikungunya. Between four and eight days after a bite, a person can develop symptoms including fever, joint pain and a rash.