Cross-border investigation of a Shigella sonnei outbreak in a group of Norwegian tourists after a trip to Russia.

In early September 2006, the Norwegian Institute of Public Health was alerted to an outbreak of Shigella sonnei infections (shigellosis) among 23 Norwegian passengers who had taken a bus tour from Kirkenes, Norway to Murmansk, Russia. The trip lasted from 27 to 31 August, and the group stayed in various hotels and visited several restaurants in both Kirkenes and Murmansk during this period. Stool samples from three ill passengers yielded S.