Quarantine was first applied for
1. Quarantine (40 day detention) is the restriction of activities of well persons (HEALTHY CONTACTS) or animals who have been exposed to a communicable disease or are traveling from a disease-endemic-zone to a non-diseased-area for a period of time equivalent to the LONGEST KNOWN INCUBATION PERIOD of that specific communicable disease. This is done to prevent contact with individuals who are not exposed to a communicable disease and to prevent transmission to an area free of disease. It was for the first time applied for Plague.
2. Modified quarantine refers to selective partial limitation of movement of contacts of communicable diseases to protect susceptible individuals from contracting disease. Exclusion of children with chickenpox and measles from regular school is an example.