Zhengzhou Photo:VCG

Zhengzhou, Central China's Henan Province, expanded lockdown area of residential communities and escalated epidemic control as the local outbreak continues to spread within the city. The city is just recovering from a severe flood disaster which caused nearly 300 deaths in the capital city.

The sealed-off area has been expanded to about 28 square kilometers, with 12 streets newly added to the list. All residents in the area are restricted to only "enter but no leave," and all public places, except for grocery stores and pharmacy, have been shut down, said Zhengzhou authorities on Tuesday. 

Nucleic acid tests will be carried out for all personnel on the first, fourth and seventh days after the lockdown. 

Three streets were raised to medium-risk regions on Tuesday, bringing the total number to six, along with one high-risk region. 

Zhengzhou reported two new local confirmed cases and seven asymptomatic patients on Wednesday. It launched a massive nucleic acid test for all residents on Saturday.

Most of the confirmed and asymptomatic COVID-19 patients were related to the Sixth Hospital in Zhengzhou, a designated hospital for treatment of overseas arrivals who are infected with COVID-19, including cleaning staff, medical staff, inpatients and their escorts. 

There have been speculations about whether the severe rainstorm and flood disaster caused the spread of the virus. 

Some experts said that the transmission path of the virus needs to be further traced by the authorities and the heavy rain should be taken into account.

The virus strains of the first two infected patients in the city were found to be highly homologous with the ones of the COVID-19 patients who returned from Myanmar and received treatment at the Sixth Hospital, both being Delta mutant strains, said local authorities at a press conference on Monday.