Onset and duration of symptoms and timing of disease transmission of 2009 influenza A (H1N1) in an outbreak in Fukuoka, Japan, June 2009.

The first confirmed case of 2009 influenza A (H1N1) in Fukuoka, Japan was reported in early-June 2009. The disease rapidly spread through this area, mainly in schools, until there were no new cases detected 3 weeks later. We describe herein the clinical characteristics of this novel infection that came to light through the investigation of this outbreak.