Historically leprosy, yellow fever, cholera, and tuberculosis have occasioned public quarantine efforts. AIDS fits the quarantine model derived from past quarantine efforts. The model components are the disease's association with feared social subgroups, transmission through means the public has deemed unlawful or distasteful, the potential for the spread of the disease beyond the rejected groups to the public at large, and a lengthy period of infectiousness without hospital confinement. The quarantine model may be undermined by evidence that sustained quarantine for large numbers of persons has not been successful in the past. Additionally, public fears can be quelled by information that AIDS is not spread through casual social contact. Evidence of the growing success of educational programs among high-risk groups can also counter public fears. The quarantine model, however, is likely to be fueled by any evidence that AIDS is spreading significantly beyond the groups (intravenous drug users and homosexuals) currently associated with it. 20 references.