CHARLOTTE, N.C. (AP) — Three missionaries who worked with patients infected with the Ebola virus in Liberia have returned to the United States.

Health officials say the aid worker and two doctors are all healthy, but they will be kept in quarantine in Charlotte to make sure they do not have Ebola. The quarantine will last at least three weeks.

David Writebol is one of the missionaries who returned by private charter plane late Sunday night. His wife, Nancy, remains in isolation in an Atlanta hospital after she was returned to the United States to be treated for the virus last week.

The missionaries are with Charlotte-based SIM USA and will be staying in a private section of the organization’s 90-acre headquarters.

Copyright 2014 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.