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. Lagomorph carcasses from the area yielded evidence of infection with A1 and A2, as well as F. tularensis subsp. holarctica. These findings indicate that multiple subspecies and clades can cause disease in a localized outbreak of tularemia