CHENGDU, Dec. 7 (Xinhua) -- Chengdu, the capital of southwest China's Sichuan Province, reported two new domestically transmitted COVID-19 cases on Monday, local authorities said.

The patients are a couple. A 69-year-old woman with the surname of Lu visited a local hospital in Pidu District after experiencing symptoms of a cough on Sunday. She tested positive for the coronavirus on Monday and was diagnosed as a confirmed COVID-19 patient. Later in the day, her husband, 71, was also diagnosed as a COVID-19 patient.

According to the epidemiological investigations, 55 close contacts have been traced and placed under medical observation.

Swab samples of 21,615 people in the city have been collected for nucleic acid tests by Monday evening.

A total of 362 environmental and food samples have been collected. Among them, 126 nucleic acid tests have been completed, with four positive for coronavirus and seven suspected as positive.

The couple's home, neighborhoods, and the places where they had visited in the past 14 days are being disinfected.

The provincial and municipal disease control and public security departments are continuing the source tracing of the COVID-19 domestic transmission. Gene sequencing of the virus samples is jointly carried out by the provincial and municipal disease control departments.