title: An outbreak of Pontiac fever with respiratory distress among workers performing high-pressure cleaning at a sugar-beet processing plant.
abstract: BACKGROUND
  In August 2000, the Minnesota Department of Health was notified of and investigated an outbreak of febrile respiratory illness among workers at a sugar-beet processing plant.
  
  
  METHODS
  A case was defined as fever and respiratory symptoms occurring in a worker at the sugar-beet plant on or after 31 July 2000. Case patients were interviewed, medical and work records were reviewed, and clinical samples were obtained. The plant was inspected, and environmental samples were collected.
  
  
  RESULTS
  Fourteen of 15 case patients performed high-pressure water cleaning in the confined space of an evaporator vessel. Symptoms included fever and chills (100%), chest tightness (93%), cough (80%), and shortness of breath (73%). In case patients, median temperature was 39.4 degrees C, median oxygen saturation was 93%, and median white blood cell count was 12x10(3) cells/ mu L. Four (29%) of 14 case patients showed evidence of Legionella pneumophila exposure, according to serologic testing. Water sources contained up to 10(5) cfu/mL of L. pneumophila and 22,200 endotoxin units/mL.
  
  
  CONCLUSIONS
  Outbreak features were consistent with Pontiac fever. Respiratory symptoms, which are atypical for Pontiac fever, could be attributed to a high exposure dose of L. pneumophila from confined-space aerosolization or to endotoxin exposure. This outbreak demonstrates the potential occupational hazards for those performing high-pressure cleaning in confined spaces.
authors.affiliation: Minnesota Department of Health, Minneapolis, Minnesota 55414, USA.
authors.forename: Mei Lin
authors.initials: ML
authors.lastname: Castor
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Wagstrom
authors.forename: Richard N
authors.initials: RN
authors.lastname: Danila
authors.forename: Kirk E
authors.initials: KE
authors.lastname: Smith
authors.forename: Timothy S
authors.initials: TS
authors.lastname: Naimi
authors.forename: John M
authors.initials: JM
authors.lastname: Besser
authors.forename: Keith A
authors.initials: KA
authors.lastname: Peacock
authors.forename: Billie A
authors.initials: BA
authors.lastname: Juni
authors.forename: John M
authors.initials: JM
authors.lastname: Hunt
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Bartkus
authors.forename: Steven R
authors.initials: SR
authors.lastname: Kirkhorn
authors.forename: Ruth
authors.initials: R
authors.lastname: Lynfield
mesh_terms: D004781:Environmental Exposure; D005221:Fatigue / Q000209:etiology; D005334:Fever / Q000209:etiology; D005511:Food Handling; D019649:Food Industry; D006801:Humans; D008910:Minnesota / Q000453:epidemiology; D008969:Molecular Sequence Data; D009784:Occupational Diseases / Q000453:epidemiology*; D012128:Respiratory Distress Syndrome / Q000453:epidemiology*; D013395:Sucrose; D014876:Water Pollution
chemical_list: D013395:Sucrose