An outbreak of travel-associated Legionnaires disease and Pontiac fever: the need for enhanced surveillance of travel-associated legionellosis in the United States

J Infect Dis. 2002 Jan 15;185(2):237-43. doi: 10.1086/338060. Epub 2001 Dec 18.


Travel-associated outbreaks of legionnaires disease (LD) and combined outbreaks of LD and Pontiac fever (PF) are rarely identified. During one travel-associated combined outbreak at a hotel, a cohort study of potentially exposed persons and an environmental investigation were performed. Two LD and 22 PF cases were identified. Legionella pneumophila serogroup 6 (Lp6) isolates from the index patient and the hotel whirlpool spa were found to be identical by amplified fragment-length polymorphism typing. Disease occurred in 10 of 26 guests who were exposed to the spa versus 2 of 29 guests who were exposed only to the pool area (38% vs. 7%; P=.005). Immunoglobulin M (IgM) antibody to the outbreak Lp6 strain was more common among persons with PF (4 of 9) than among non-ill persons (2 of 32) (44% vs. 6%; P=.02). Spa exposure correlated with disease (P=.001) and IgM seropositivity (P=.007). New laboratory techniques facilitate outbreak investigation; to expedite outbreak interruption and measure the impact of travel-associated legionellosis, surveillance must be improved.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Child
  • Child, Preschool
  • Cohort Studies
  • Disease Outbreaks*
  • Female
  • Humans
  • Legionella pneumophila / isolation & purification
  • Legionnaires' Disease / epidemiology*
  • Legionnaires' Disease / prevention & control
  • Male
  • Middle Aged
  • Travel*
  • United States / epidemiology
  • Water Microbiology*