The cities of Dalian and Fushun in Liaoning province published notices on Saturday to find residents that might have contact with a confirmed COVID-19 case in Harbin, capital city of Heilongjiang province.
 
An 87-year-old male confirmed case underwent treatment for a cerebral stroke at two hospitals in Harbin between April 2 to 9, leading to several patients and their family members in the same ward become infected, according to the Harbin health commission.
 
Local residents who came in contact with the patient have been asked to report immediately and receive tests, according to statements of virus control and prevention departments in Dalian and Fushun.
 
Since April 9, the province has reported 38 confirmed cases of locally transmitted COVID-19 and 23 local asymptomatic cases as of Saturday, the latest data from the provincial health authority said. And 36 confirmed cases and 18 of the asymptomatic cases were from Harbin city.
 
A 46-year-old female was confirmed positive in Fushun after accompanying her father who was hospitalized at First Affiliated Hospital of Harbin Medical University between April 2 to 10, according to Fushun health commission.
 
She returned to Fushun on April 12 and was diagnosed on April 16.
 
All the cases in Harbin have manifested the clear characteristics of cluster infections, said Liu Nan, a health commission official.
 
In the cluster infections in Harbin, a resident who returned from the United States on March 19 reportedly transmitted the virus to her upstairs neighbor, who in turn infected four others, including Chen, at the dinner table.
 
All the teachers and senior students that have resumed work in high schools and secondary vocational schools will receive free coronavirus tests, Liu said at a news conference on Saturday, adding that during the process of testing, students will be asked to have online courses at home.