title: Contaminated drinking water in one town manifesting as an outbreak of cryptosporidiosis in another.
abstract: In early 1992 we identified an outbreak of cryptosporidiosis in Oregon and sought to identify and control its source. We used a series of studies to identify risk factors for illness: (i) a case-control study among employees of a long-term-care facility (LTCF); (ii) a matched case-control study of the general community; (iii) a cohort study of wedding attendees; and (iv) a cross-sectional survey of the general community. Drinking Talent water was associated with illness in the LTCF (OR = 22.7, 95 % CI = 2.7-1009.0), and in the community (matched OR = 9.5, 95% CI 2.3-84.1). Drinking Talent water was associated with illness only among non-Talent residents who attended the wedding (P < 0.001) and in the community (RR = 6.5, 95 % CI 3.3-12.9). The outbreak was caused by contaminated municipal water from Talent in the absence of a discernible outbreak among Talent residents, suggesting persons exposed to contaminated water may develop immunity to cryptosporidiosis.
authors.affiliation: Oregon Health Division, Center for Disease Prevention and Epidemiology, Portland 97232, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: McAnulty
authors.forename: W E
authors.initials: WE
authors.lastname: Keene
authors.forename: D
authors.initials: D
authors.lastname: Leland
authors.forename: F
authors.initials: F
authors.lastname: Hoesly
authors.forename: B
authors.initials: B
authors.lastname: Hinds
authors.forename: G
authors.initials: G
authors.lastname: Stevens
authors.forename: D W
authors.initials: DW
authors.lastname: Fleming
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003457:Cryptosporidiosis / Q000453:epidemiology*; D003458:Cryptosporidium / Q000302:isolation & purification*; D003967:Diarrhea / Q000469:parasitology*; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D007223:Infant; D008134:Long-Term Care; D008297:Male; D008875:Middle Aged; D009922:Oregon / Q000453:epidemiology; D014871:Water Microbiology; D014881:Water Supply