Travel-associated cases of Legionnaires’ disease in the United States, 2015–2016

Abstract

BackgroundRecent travel is associated with ~20% of reported Legionnaires’ disease (LD) cases worldwide. MethodsWe analyzed LD cases reported to the Centers for Disease Control and Prevention (CDC) during 2015–2016. Travel-associated cases met case criteria for confirmed LD in someone who spent ≥1 night away from home during the 10 days before symptom onset. Most analyses were limited to travel-associated, public accommodation stay (TAPAS) cases. We used reported travel dates to estimate the number of TAPAS cases acquired during travel. ResultsOf 12,200 LD cases reported among U.S. residents, 12.3% were travel-associated; 8.7% were TAPAS. Median patient age for TAPAS cases was 61 years; 64.4% were male; 67.3% were white; 77.9% were non-Hispanic; 96.1% were hospitalized; 4.5% died. Among 887 TAPAS cases involving U.S. destinations, an estimated 29.8% were acquired during travel; 4.28 TAPAS cases were reported, and an estimated 1.10 TAPAS cases were acquired during travel, per 10,000,000 hotel room nights booked. Sixty-eight U.S. TAPAS clusters were detected. ConclusionsWhile acquisition during travel accounted for a relatively small proportion of all LD cases, clusters of TAPAS cases were frequently detected. Prompt notification of these cases to CDC facilitates cluster detection and expedites intervention.