This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
EITor vibrio may be differentiated from classical vibrio by fact that EITor vibrio - 
Select and explain. 
A. Agglutinate chicken and sheep erythrocytess, B. Resistant to classical phage IV, C. Resistant to polymyxin B-5 unit disc, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: Ans. is 'd' i.e., All of the above El Tor vibrio o It is much hardier than classical vibrios, capable of surviving in the environment much longer. o The severity of illness is much less, with a large propoion of mild and asymptomatic infections. o Moality is low and the carrier rate is high. o Fewer secondary cases in affected families (secondry attack rate is less) - Park