The infectivity of a patient with diphtheria is -: (A) Till cough subsides, (B) Till patient is febrile, (C) Life long, (D) For 15 days after infection
Answer is D. Unless treated, the period of infectivity may vary from 14 to 28 days from the onset of the disease, but carriers may remain infective for much longer periods. Ref:PARK&;S TEXTBOOK OF PREVENTIVE AND SOCIAL MEDICINE , 23rd edition , Page 160