This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiology, Subject name: Social & Preventive Medicine
Disease highly transmitted during incubation period is - 
Select and explain. 
A. Peussis, B. Cholera, C. Measles, D. Brucellosis
A: Peussis
Answer: A: Peussis 
Explanation: Whooping cough is most infectious during the catarrhal stage. The infective period may be considered to extend from a weak after exposure to about 3 weeks after the onset of the paroxysmal stage although communicability diminishes rapidly after the catarrhal stage. (refer pgno:163 park 23 rd edition)