You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Virulence of a biological agent is defind as - and explain in detail?
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