index case

Noun

 * 1)  The first documented patient in a disease epidemic within a population or the first case of interest in an epidemiological investigation; the case of patient zero.

Translations

 * Catalan: cas índex, pacient zero
 * Finnish: indeksitapaus
 * French:
 * German:
 * Italian: caso indice, paziente zero
 * Polish: przypadek wskazujący
 * Russian:
 * Spanish: caso índice, paciente cero