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
Carriers are important source of infection in all, EXCEPT: 
Select and explain. 
A. Measles, B. Mumps, C. Diphtheria, D. Typhoid
A: Measles
Answer: A: Measles 
Explanation: Ans. is 'a' i.e. Measles Sources of infection :Measles : The only source of infection is a case of measles.Mumps : Both clinical and sub clinical casesDiptheria : 95% carriers and 5% clinical casesTyphoid : case & carriers