International Journal of Epidemiology 2000;29:1092-1098
© International Epidemiological Association 2000
Outbreak of Legionnaires' disease associated with a display whirlpool spa
a Epidemic Intelligence Service, Office of Epidemiology, Virginia Department of Health (VDH), Richmond, VA and Epidemiology Program Office, Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA.
b Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, CDC, Atlanta, GA, USA.
c Office of Epidemiology, VDH, Richmond, VA, USA.
d New River Health District, VDH, Christiansburg, VA, USA.
e Division of Parasitic Diseases, CDC, Atlanta, GA, USA.
Background Recognized outbreaks of Legionnaires' disease (LD) are rare; when they occur, they provide opportunities to understand the epidemiology of the illness and improve prevention strategies. We investigated a population-based outbreak.
Methods After the confirmation of LD in October 1996 in five people in neighbouring towns in southwest Virginia, active surveillance for additional cases was undertaken. A case-control study was conducted to identify exposures associated with illness, followed by a cohort study among employees of the facility at which the source of the outbreak was located in order to assess unrecognized exposure and illness. Samples of likely sources of LD in the facility were cultured for Legionella.
Results In all, 23 laboratory-confirmed cases of LD were eventually identified. Of the 15 cases in the case-control study, 14 (93%) reported visiting a home-improvement store, compared with 12 (27%) of 45 controls (matched odds ratio [MOR] = 23.3; 95% CI : 3–182). Among home-improvement centre patrons, 10 (77%) of 13 cases questioned recalled either visiting or walking by a display whirlpool spa, compared with 3 (25%) of 12 controls (MOR = 5.5; 95% CI : 0.7–256.0). Two cases' sputum isolates were an exact match, by monoclonal antibody subtyping and arbitrarily primed polymerase chain reaction, to a whirlpool spa filter isolate from the store. Employees reporting more exposure to the display spas were more likely to report symptoms of LD or to have an elevated titre.
Conclusions This investigation shows that LD can be transmitted from a whirlpool spa used for display only, and highlights the need for minimizing the risk of transmission of LD from all water-filled spas.
Key messages This paper describes an investigation of a population-based outbreak of Legion-naires' disease (LD). A case-control study first identified a home-improvement store as the likely source of the outbreak. An environmental investigation later confirmed that finding, as two cases' sputum isolates were an exact match, by monoclonal antibody subtyping and arbitrarily primed polymerase chain reaction, to a whirlpool spa filter isolate from the store. The spa was intended and used for display only.
Keywords Legionnaires' disease, Legionella pneumophila, outbreak, whirlpool spa, community-acquired pneumonia, legionellosis, urinary antigens
Accepted 6 June 2000
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  B. S. Fields, R. F. Benson, and R. E. Besser Legionella and Legionnaires' Disease: 25 Years of Investigation Clin. Microbiol. Rev., July 1, 2002; 15(3): 506 - 526. [Abstract] [Full Text] [PDF]
|
|