The public health agency of Seattle and King County in the US state of Washington received a call alerting it to an outbreak of acute gastroenteritis among participants at a soccer tournament held in the county one weekend.
About 2,000 children from 120 schools in Washington and Oregon participated in the tournament. The players, chaperones and organisers had eaten at many hotels and restaurants in the area. The potential fallout was huge.
Officials quickly contacted colleagues at the health departments in Washington and Oregon to help ascertain the scope and reach of the problem. At the Oregon Public Health Division, Dr William Keene, senior epidemiologist with the Acute and Communicable Disease programme, took the call.
The three health agencies swiftly co-ordinated the investigations.
Washington health officials contacted the organisers of the tournament - a task made easier by the comprehensive list of participating teams at the tournament website. Seattle and King County contacted the food establishments in the area to check for reports of food poisoning. Keene and his assistant, Dr Kimberly Repp, followed up with the known victims of gastroenteritis who were from an Oregon soccer team.
Within an hour or two, it became apparent that the outbreak was limited to members of that team, as organisers and eateries reported no complaints of illness. Although the outbreak was much more contained than Keene and his colleagues had initially feared, Keene now needed to find out how the illness had spread. Although the impact of the outbreak was limited and unremarkable, investigations led Keene to an exciting discovery that affirmed a hard-to-prove theory that scientists had held for years.