Nebraska medical officials say an American health care provider who had high-risk exposure to the Ebola virus while working in Sierra Leone will be observed at a biocontainment unit in Omaha, AP reported. Nebraska Medicine says in a statement that the unidentified patient will arrive Sunday afternoon aboard a private air ambulance. Phil Smith, medical director of the facility's biocontainment unit, says the patient "is not ill and is not contagious." He says officials will take "all appropriate precautions." The patient will be observed for possible infection during the 21-day incubation period of the disease, both by monitoring for symptoms and through blood tests. Three patients with Ebola have been treated at Nebraska Medicine, which is a clinical partner of the University of Nebraska Medical Center.