when i worked at a montessori school the norwalk virus swept through so badly that we had to close down two of the three preschool classrooms because there was no one to work in them. the teachers and majority of students were all sick. my daughter was in one of those classes and i was rubbing oil of oregano, diluted with olive oil, into her feet each night and taking the drops in juice myself. well, we were 2 of the few people to remain in good health and not contract the nasty virus. my classroom was the only one to remain open!