title: An outbreak of travel-associated Legionnaires disease and Pontiac fever: the need for enhanced surveillance of travel-associated legionellosis in the United States.
abstract: 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.
authors.affiliation: Epidemic Intelligence Service, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
authors.forename: Andrea L
authors.initials: AL
authors.lastname: Benin
authors.forename: Robert F
authors.initials: RF
authors.lastname: Benson
authors.forename: Kathryn E
authors.initials: KE
authors.lastname: Arnold
authors.forename: Anthony E
authors.initials: AE
authors.lastname: Fiore
authors.forename: Patricia G
authors.initials: PG
authors.lastname: Cook
authors.forename: L Keoki
authors.initials: LK
authors.lastname: Williams
authors.forename: Barry
authors.initials: B
authors.lastname: Fields
authors.forename: Richard E
authors.initials: RE
authors.lastname: Besser
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D016952:Legionella pneumophila / Q000302:isolation & purification; D007877:Legionnaires' Disease / Q000453:epidemiology* / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D014195:Travel; D014481:United States / Q000453:epidemiology; D014871:Water Microbiology