Influenza B virus outbreak at a religious residential school for boys in Northern Bangladesh, 2011.

Background: National media reported a febrile illness among dormitory residents of a boys' religious school. We investigated the outbreak to identify cause.

Methods: Individuals with fever (>100°F) and cough or sore throat between 1 and 13 August 2011 were influenza-like-illness (ILI) case-patients.