Linshui county in the city of Guang'an, Sichuan province, reported 15 confirmed locally transmitted COVID-19 cases and 72 local asymptomatic cases on Monday, the Guang'an city health commission said on Tuesday.

The latest statistics from the Guang'an commission show the county had accumulated 48 locally transmitted COVID-19 cases and 535 local asymptomatic cases by Monday, which has drawn growing attention to this small county's efforts in curbing the infection.

Sichuan's latest COVID-19 epidemic started in Linshui on May 9 when it reported three local asymptomatic cases.

Previous media reports claimed the first infected person detected in Linshui was a driver from a ride-hailing company who had traveled frequently between Linshui and Chongqing.

After driving back to Linshui from Chongqing on May 8, he took the initiative to take a nucleic acid test. The result was abnormal and he was quarantined for treatment, media reports said.

As the gateway to the eastern part of Sichuan, Linshui is only 90 kilometers from the main urban area of Chongqing.

However, a staff member of the Linshui county emergency response headquarters for COVID-19 said that the county's first patient was a person who had recently returned from Shanghai. The driver from the ride-hailing company had carried the person who had come back from Shanghai.

Sichuan has three medium-risk areas, all of which are in Linshui, one of the province's largest counties with a population of over 1 million.

Linshui was locked down on May 10, one day after the outbreak.

The county's inhabitants can only go shopping once every two days.

According to Yu Lidong, an information officer from the Guang'an city government information office, more than 3,000 medical workers from Guang'an, Chengdu, Bazhong and Ya'an cities in Sichuan have arrived in the county.

On Sunday, Sichuan's first gas membrane nucleic acid testing laboratory with a maximum testing capacity of 70,000 tubes per day was completed and put into operation in Linshui.

The county started three consecutive days of nucleic acid testing in order to test all its inhabitants. On Monday, more than 495,000 people were tested, according to the Guang'an city health commission.

On Friday, a makeshift hospital with 1,040 beds began operating, led by Wang Kunjie, vice-president of West China Hospital of Sichuan University and 90 medical workers.