The index case or primary case is the initial patient in the population of an epidemiological investigation. The index case may indicate the source of the disease, the possible spread, and which reservoir holds the disease in between outbreaks. The index case is the first patient that indicates the existence of an outbreak. Earlier cases may be found and are labeled primary, secondary, tertiary, etc. "Patient Zero" was used to refer to the index case in the spread of HIV in North America.
Read more about Index Case: Gaëtan Dugas Case ("Patient Zero"), Other Index Patients, In The Media
Famous quotes containing the words index and/or case:
“Exile as a mode of genius no longer exists; in place of Joyce we have the fragments of work appearing in Index on Censorship.”
—Nadine Gordimer (b. 1923)
“I do not allow myself to be moved by anything except the law. If there has been a mistake in the law, or if I think there has been perjury or injustice, I will weigh the petition most carefully, but I do not permit myself to be moved by more harrowing details, and I try to treat each case as if I was reviewing it or hearing it for the first time from the bench.”
—William Howard Taft (1857–1930)