LIVERMORE FALLS — The Maine Center for Disease Control and Prevention has traced the period of infectiousness of a Regional School Unit 73 employee with COVID-19 back to Sept. 24, Superintendent Scott Albert advised staff and students in a letter Thursday.

Albert announced Wednesday that the employee, who works throughout the three-town district, tested positive for the coronavirus that day but had not been in the schools and therefore, according to the CDC, no further action was needed.

On Thursday, Albert said the contact tracer for the CDC determined the timeline of infectiousness went back to Sept. 24.

Staff and students who have had close contact with the employee have been notified and told to quarantine for 14 days and be tested, the superintendent said.

According to the CDC on Thursday, all secondary contacts, including employees and students, are safe to continue daily life without any restrictions.

The district will continue to share additional information as it becomes available from the Maine CDC.

RSU 73 includes students from Jay, Livermore and Livermore Falls, and some from Fayette. Spruce Mountain Primary School is in Livermore, the elementary, middle and high schools are in Jay and the adult education program operates from the central office in Livermore Falls.

In August, the RSU 73 board of directors approved two-day a week classroom instruction with students in cohort A attending classes Monday and Tuesday and those in cohort B Wednesday and Thursday. The cohorts would be divided by last names, with members of combined families attending the same cohort. Families could opt for fully remote instruction.

As of Oct. 1, Spruce Mountain High School had 136 students in cohort A, 130 in cohort B and 105 fully remote students.

The middle school’s numbers were 137 in A, 125 in B and 92 remote.

The elementary school’s numbers were 111 in A, 116 in B and 83 remote.

The primary school’s numbers were 139 in A, 128 in B and 67 remote.