Pingdu, a county-level city in Qingdao, Shandong province, reported a confirmed COVID-19 case and another asymptomatic case on Wednesday, the local health authority said.

The confirmed case is a 38-year-old man surnamed Zhang and the asymptomatic case is his wife, 40-year-old Wang, according to the Qingdao municipal health commission.

Both left the city of Suihua in Northeast China's Heilongjiang province on Jan 11, drove to Hezhou, South China's Guangxi Zhuang autonomous region by highways, and returned to Pingdu city on Jan 14, according to a notice issued by the Pingdu city authority on Thursday morning.

The city of Suihua is one of places in China experiencing recent coronavirus outbreaks.

When they arrived at Pingdu city, they headed for the local hospital for nucleic acid testing.

The notice detailed the couple's travel records and asked residents to enhance epidemic control and prevention measures.

The couple had been tested twice and the results were all negative. However, the man's body temperature rose to 38.3 C with symptoms of coughing on Tuesday evening. They went to a fever clinic the next day and in the afternoon their nucleic acid test results both came out positive. Now they have been quarantined and received treatment.

As of 7 am on Thursday, the local health authority has traced 77 of the couple's contacts and 305 of the contacts' contacts. All are under medical observation, Qingdao municipal health commission said.