Epidemiological triad includes all except: (A) Host, (B) Environment, (C) Agent, (D) Investigator
Answer is D. The Epidemiologic Triad consists of an external agent, a host and an environment in which host and agent are brought together, causing the disease to occur in the host. Ref: 25th edition, Park's Textbook of Preventive and Social Medicine, Page no. 39