The city of Manzhouli, in the Inner Mongolia autonomous region, reported eight positive results in its second round of coronavirus tests, Friday afternoon to Sunday, for its 203,378 residents.

"Seven people were diagnosed as having confirmed symptoms of COVID-19, and one was diagnosed as asymptomatic," Manzhouli Vice-Mayor Guo Xiaofang said at a news conference on Tuesday.

Epidemiological investigations of the new cases are being conducted, she said, adding that more than 3,800 close contacts of the patients have been traced and put under quarantine for medical observation.

Manzhouli, the largest rail land port on the China-Russia border, has been strictly checking the Russian drivers and reducing the number of Chinese workers at the port's freight yards, and it has also increased disinfection measures to reduce the risk of imported infections

Manzhouli, the largest rail land port on the China-Russia border, has been strictly checking the Russian drivers and reducing the number of Chinese workers at the port's freight yards, and it has also increased disinfection measures to reduce the risk of imported infections.

The city has adopted strict measures among the residential communities in three medium-risk areas for COVID-19.

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"Special workers have been assigned to provide for the needs of people quarantined in each unit of the residential buildings," said Guo.

In addition, two professional disinfection teams have finished disinfecting where the patients live and work as well as where people have been isolated, a total area of more than 230,000 square meters, said Wang Hongquan, director of the city's disease control and prevention center.

"It is necessary to wear masks and to go to a hospital immediately if you have symptoms, including fever, physical weakness and dry cough," he said.

As of Tuesday, the city had reported 18 local confirmed cases, two suspected cases and two asymptomatic cases since the first two confirmed cases were reported on Nov 21.

In Shandong province, an asymptomatic coronavirus infection was reported Monday night in Jiaozhou, a county-level city in Qingdao, the Qingdao health commission said, adding that the man was among those who had received routine nucleic acid tests.

A total of 486 contacts have been found and all were tested. Of those, 478 results so far came back negative.

Cold-chain management

In response to the new cases and the recent outbreak weeks ago in some domestic cities, such as Tianjin, cold-chain food management has been given extra attention, and stricter controls have been placed on related matters like storage and delivery since they were identified as possible sources of infection.

READ MORE: China vows to stem COVID-19 spread through imported foods

Jinan, Shandong province, released a notice on Tuesday, saying that that it began using special warehouses to collect imported frozen food that lacks inspection, quarantine and disinfection documentation.

Beijing will tighten epidemic prevention in the transportation sector including strengthening the management of airport freight areas and related business units and conducting regular nucleic acid testing workers in freight areas.

Zhao Ruixue in Jinan and Du Juan in Beijing contributed to the story.

Contact the writers at zhouhuiying@chinadaily.com.cn