Mpox is caused by a virus transmitted to humans by animals but can also spread from person to person through close physical contact.

It causes fever, muscular aches and large boil-like skin lesions, and can be deadly.

The World Health Organization (WHO) declared a global health emergency over the virus in August and renewed it in November following an outbreak in the Democratic Republic of Congo (DRC), where it has killed more than 1,000 people.

Two days after the WHO's August declaration, China announced it would screen people entering the country for mpox over the next six months.

Chinese health authorities said Thursday that they had discovered a cluster outbreak of the mpox strain Clade 1b, with the source of infection believed to be someone with a record of living in the DRC.

Four people who had close contact with the patient were found to be infected by the strain and were showing relatively mild symptoms of rashes and blisters, the Chinese Center for Disease Control and Prevention said in a statement.

"The infected and at-risk people are receiving medical treatment and health observation, and the outbreak has been effectively handled," it added.

To date, no cases have been found among other contacts, the health authority said.

Cases of mpox have been reported in more than 120 countries since 2022, according to the WHO.