This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Measles, Subject name: Social & Preventive Medicine
In all of the following diseases chronic carriers are found except: 
Select and explain. 
A. Measles, B. Typhoid, C. Hepatitis B, D. Gonorrhoea
A: Measles
Answer: A: Measles 
Explanation: Ans. is 'a' i.e. Measles In measles the only source of infection is a case of measles. Carriers are not known to occur.For more see Q no. 31 of Dec 1998.