In control of communicable diseases, the period of quarantime in respect of a disease is determined by-

.quarantine has been defined as the limitation of freedom of movement of such well persons or domestic animals exposed to communicable disease for a period of time not longer than the longest usual incubation period of the disease, in such a manner as to prevent effective contact with those not so exposed,so its communicability can be attributed to the incubation period. ref:park&;s textbook,22nd edition,pg no 112