URUMQI, Aug. 18 (Xinhua) - Three asymptomatic COVID-19 cases previously reported in northwest China's Xinjiang Uygur Autonomous Region were found to be infected with the Delta variant, local health authorities said Wednesday.
The cases were identified in the port area of Alataw, Bortala Mongolian Autonomous Prefecture, during routine nucleic acid testing on Aug. 15.
Based on further gene sequencing analysis and epidemiological investigation, it was concluded that the cases are not related to recent locally transmitted or imported cases in other parts of China. The infections are highly likely to be caused by the virus from abroad, according to the regional center for disease control and prevention.
The patients had no history of travelling abroad, nor did they leave the region during the 14 days before they tested positive for the virus. They all recorded no traveling history to the country's medium- or high-risk areas for COVID-19 and had no close contact with any COVID-19 cases before, the center said.
As of 8 a.m. Wednesday, Xinjiang launched three rounds of massive nucleic acid testings in the prefecture since the three asymptomatic cases were reported. No positive results for the coronavirus have been found.
Meanwhile, the region had registered no other new cases by the end of Tuesday.