Medical workers collect swab samples for residents at Tianshan District in Urumqi, northwest China's Xinjiang Uygur Autonomous Region, July 20, 2020. Urumqi is carrying out free nucleic acid tests for all residents and people who are visiting the city, in a bid to screen for novel coronavirus infections and reduce the risk of the epidemic spread.Photo:Xinhua

Shufu county of Kashi Prefecture in Northwest China's Xinjiang Uygur Autonomous Region reported one asymptomatic COVID-19 case Saturday night, who was found during a routine testing, the local Center for Disease Control and Prevention said.

A 17-year-old woman, a villager in Zhanmin town of Shufu, was tested positive during regular nucleic acid testing and was diagnosed as an asymptomatic case by medical experts, according to the notification released at 9:40 pm.

The person is under medical observation in a designated hospital in Kashi. She shows no symptoms such as fever or cough.

The local CDC in Shufu launched an emergency response and started epidemiologic investigation. People in close contact with the patient have all been put under medical observation. Nucleic acid testing is also being carried out.

A comprehensive investigation of places where the asymptomatic person has been active is being carried out, and relevant information will be released to the public in a timely manner, said the notification.

Medical departments reminded the public to enhance personal prevention and cooperate with related departments on virus prevention.

All residential communities in Kashi have prohibited entry or exit starting Saturday. The Kashi airport have been operating normally, but passengers are required to first take nucleic acid test and receive negative result before they are allowed to board a plane for departure.

According to media reports, Shufu has a higher incidence of tuberculosis among its residents due to their living habits and other reasons. Experts said a combination of TB and COVID-19 would add difficulty for medical treatment.

Police in Kashi released a notice at around 5 pm Saturday on Sina Weibo, calling on residents to wear masks and not listen to or spread rumors. But the post was later removed.

The police's notice came after many flights at the Kashi Airport were canceled. Since 4:25 pm, more than 20 flights with the destination of Kashi have been canceled or returned, or have landed in another airport, the Global Times learned. Most flights leaving Kashi were canceled after 5 pm.

"We have not received any notice involving a public health event or COVID-19. Cancellation of flights is the decision of airline companies," an employee at the security check of Kashi Airport told the Global Times on Saturday afternoon.

A number of residents in Kashi reached by the Global Times said they received a phone message from the local government on Saturday, which said that Kashi would conduct a sweeping nucleic acid test for all residents to meet epidemic prevention requirements for the winter season. 

During the testing period, in order to achieve the effect, the city will stop the flow of people and vehicles, according to the message. It calls for residents to cooperate and pay attention to official notices.

At least two Kashi residents confirmed with the Global Times that they have been informed orally about the sweeping nucleic acid test.

An employee at the Kashi People's Hospital told the Global Times on Saturday night that residents should wait for notification from communities. "If your community tells you to do nucleic acid test, you should do it."

But employees at two other local hospitals said they have not received any notice about a large-scale nucleic acid tests yet, before the announcement of the asymptomatic case.

A resident from Shufu county of Kashi said that the county is under lockdown and the county government is screening for COVID-19 cases.

On Sina Weibo, some photos and videos posted Saturday afternoon showed supermarkets in Kashi crowded with people shopping for daily necessities such as toilet paper and vegetables.

"We are still open and are selling goods," Mireban, a saleswoman from a wine shop in the old town of Kashi, a local landmark, told the Global Times on Saturday afternoon.