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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Virulence of a biological agent is defind as -
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The correct answer is  For an infectious agent, infectivity refers to the propoion of exposed persons who become infected. Pathogenicity refers to the propoion of infected individuals who develop clinically apparent disease. Virulence refers to the propoion of clinically apparent cases that are severe or fatal. Ref: 25th edition, Park's Textbook of Preventive and Social Medicine, Page no. 43