This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable diseases, Subject name: Social & Preventive Medicine
Isolation is not needed for measles due to - 
Select and explain. 
A. There are healthy carriers, B. Carriers are convalascents, C. The infectivity in diseased is low, D. There are incubatory carriers
D: There are incubatory carriers
Answer: D: There are incubatory carriers 
Explanation: Transmission directly from person to person by droplet infection from 4 days before onset of rash until 4days thereafter. REF. PARK'S TEXTBOOK OF PREVENTIVE AND SOCIAL MEDICINE 21ST EDITION. PAGE NO - 147