A large, travel-associated outbreak of legionellosis among hotel guests: utility of the urine antigen assay in confirming Pontiac fever.

Background: During March 2004, a large outbreak of legionnaires disease and Pontiac fever occurred among hotel guests in Oklahoma. An investigation was conducted to identify the source and evaluate the utility of the Legionella urine antigen assay and serologic testing for the identification of Pontiac fever.

Methods: A retrospective cohort investigation of hotel guests and employees and an environmental evaluation were performed.