This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Virology Pa-2 (RNA Virus Pa-1,2 & Miscellaneous Viruses), Subject name: Microbiology
Infectivity period of measles is: 
Select and explain. 
A. 2 days before and 4 days after appearance of rash, B. 4 days before and 5 days after appearance of rash, C. 4 days before and 1 days after appearance of rash, D. Entire incubation period
B: 4 days before and 5 days after appearance of rash
Answer: B: 4 days before and 5 days after appearance of rash 
Explanation: Infectivity period :-:Period of communicability is the time during which an infectious agent may be transferred directly or indirectly from an infected person to another person Measles patients are infectious from 4 days before to 5 days after the onset of rash. Infectivity period of other diseases:- Chicken pox patients are infectious from 2 days before 5 days after the onset of rash. Mumps patients are infectious from 1 week before to 2 weeks after the onset of parotitis. Rubella patients are infectious from 1 week before to 1 week after the onset of rash.