Tularemia outbreak associated with outdoor exposure along the western side of Utah Lake, Utah, 2007.

Objectives: In 2007, a localized outbreak of tularemia occurred among visitors to a lodge on the western side of Utah Lake, Utah. We assessed risk factors for disease and attempted to identify undiagnosed clinically compatible illnesses.

Methods: We conducted a retrospective cohort study by recruiting all people who had visited the lodge on the western side of Utah Lake from June 3 to July 28, 2007.

Multiple Francisella tularensis subspecies and clades, tularemia outbreak, Utah.

In July 2007, a deer fly-associated outbreak of tularemia occurred in Utah. Human infections were caused by 2 clades (A1 and A2) of Francisella tularensis subsp. tularensis.