Xiao Yao doesn't know when or where he caught the new coronavirus.

He suspects it happened on his train journey home to celebrate the Lunar New Year in Jingzhou city, in central China's Hubei province.

The 27-year-old, who works in the southwest city of Chengdu, only realized something was amiss as the clock ticked midnight into the year of the rat on Jan. 25.

"I suddenly began to feel that my body was very warm, and I began to panic," he told AFP.