the earliest documented case of a disease that is included in an epidemiological study
First case in a group to come to medical/scientific attention; case being studied.
The first case in a family or other defined group to come to the attention of the investigator.
The first case of a disease.
First disease case in an epidemic within a population.
Index Case is an American Heavy Metal/Hard Rock band, who hails from Indianola, Iowa.
The index case or patient zero is the initial patient in the population sample of an epidemiological investigation. Patient zero is a somewhat less specific term than index case and is sometimes used to refer to the central patient in an epidemiological investigation rather than the first patient. When used in general to refer to such patients in epidemiological investigations, the term is not capitalized.