[Pandemic influenza (H1N1) 2009 Outbreak in a Military Academy: start of community circulation in Spain].

Background: On May 19, 2009, 21 cases of influenza-like illness were reported among soldiers from an Engineering Military Academy (ACING) in Hoyo de Manzanares, Spain. In the context of an influenza A (H1N1)2009 global alert, it was decided to investigate a possible pandemic influenza outbreak. To describe a possible outbreak of influenza A (H1N1)2009 in a Military Training Centre and to describe the measures adopted for transmission control of this new infection.