O'FALLON — A 34-year-old Missouri teacher has died after a three-week-long hospitalization with COVID-19.

AshLee DeMarinis taught social skills and special education at John Evans Middle School in the Potosi School District in eastern Missouri. Superintendent Alex McCaul announced her death in a letter dated Sept. 7 that was posted on the district's Facebook page. The letter didn't cite a cause of death.

But DeMarinis' sister, Jennifer Heissenbuttel, said DeMarinis had been hospitalized with the coronavirus and that she died Sunday.

Heissenbuttel said her sister had not yet begun teaching students when she became ill last month, but that she had returned to the classroom to prepare for the school year.

McCaul, in a phone interview, said contact tracing has found that DeMarinis had no close contact with any other teachers or staff. Health officials have not determined how DeMarinis contracted the virus.

The district's school year began Aug. 24 with in-person classes, though students can opt to attend classes virtually. McCaul said three teachers and six students have tested positive, but all of the students and two of the teachers have since been cleared to leave quarantine.

McCaul's letter said a district crisis intervention team will help students, staff and parents deal with the loss.

"Ms. DeMarinis was a wonderful teacher loved by students, staff and members of our community," McCaul wrote. "Her commitment and passion for her students and community to succeed should be an inspiration for all of us. Ms. DeMarinis touched many lives as an educator and will be missed dearly by our community."

DeMarinis' death is among 1,661 in Missouri since the pandemic began. As of Tuesday, Missouri had reported 95,113 confirmed cases, including 269 in Washington County, Potosi's county. Tracking from Johns Hopkins University shows that Missouri's per capita number of cases is among the six highest in the country.

Potosi is about 70 miles (115 kilometers) southwest of St. Louis. 

Private and parochial schools also are dealing with the pandemic. Two Catholic grade schools in St. Louis County will close for two weeks after a staff member who travels between them had a presumed-positive case of COVID-19, the  St. Louis Post-Dispatch  reported.

St. Louis County health officials recommended the temporary closures. Students will attend classes virtually while the schools are cleaned, a spokeswoman for the Archdiocese of St. Louis said.