Quarantine is defined as the limitation of freedom of movement of persons or animals that have been exposed to a communicable disease for a period of time equal to the longest usual incubation period of the disease, in such manner as to prevent effective contact with those not so exposed. If the disease is one requiring quarantine of the contacts in addition to isolation of the case, the local health officer shall determine the contacts who are subject to quarantine, specify the place to which they shall be quarantined, and issue instructions accordingly. He shall insure that provisions are made for the medical observation of such contacts as frequently as necessary during the quarantine period.