Quarantine is the practice of isolating a sick person from people who are not sick. Quarantine decreases the spread of communicable diseases by limiting the amount of people who are exposed to airborne germs.

The correct spelling of the word is quarantine(isolation, as for contagious diseases).

Quarantine is used to temporarily keep well people who have or may have come into contact with certain diseases in confinement, to see if they become ill. Federal isolation and quarantine is authorized for the communicable diseases of cholera, diphtheria, infectious tuberculosis, plague, smallpox, yellow fever, viral hemorrhagic fevers, SARS, or flu that can cause a pandemic.

If a disease is communicable, that means that it can be spread from person to person. Isolation is important for people with communicable diseases so that the disease does not spread to other people and cause an epidemic.

Because non-communicable diseases are not passed from one person to another - communicable diseases are.