Up to 50,000 pets had been left alone at home in Wuhan, Lao Mao estimated, based on the number of people who left the city in Hubei province.

“The volunteers on our team, me included, have saved more than 1,000 pets since Jan. 25,” said Lao Mao, declining to disclose his real name because he did not want his family to know he was out and about in the city.

“My phone never stops ringing these days. I barely sleep.”

Without intervention, the pets will starve to death. Many owners, either in quarantine or stranded in other provinces and countries, have sought help from animal lovers like Lao Mao on social media.