title: Preventing community-wide transmission of Cryptosporidium: a proactive public health response to a swimming pool-associated outbreak--Auglaize County, Ohio, USA.
abstract: The incidence of recreational water-associated outbreaks in the United States has significantly increased, driven, at least in part, by outbreaks both caused by Cryptosporidium and associated with treated recreational water venues. Because of the parasite's extreme chlorine tolerance, transmission can occur even in well-maintained treated recreational water venues (e.g. pools) and a focal cryptosporidiosis outbreak can evolve into a community-wide outbreak associated with multiple recreational water venues and settings (e.g. childcare facilities). In August 2004 in Auglaize County, Ohio, multiple cryptosporidiosis cases were identified and anecdotally linked to pool A. Within 5 days of the first case being reported, pool A was hyperchlorinated to achieve 99·9% Cryptosporidium inactivition. A case-control study was launched to epidemiologically ascertain the outbreak source 11 days later. A total of 150 confirmed and probable cases were identified; the temporal distribution of illness onset was peaked, indicating a point-source exposure. Cryptosporidiosis was significantly associated with swimming in pool A (matched odds ratio 121·7, 95% confidence interval 27·4-∞) but not with another venue or setting. The findings of this investigation suggest that proactive implementation of control measures, when increased Cryptosporidium transmission is detected but before an outbreak source is epidemiologically ascertained, might prevent a focal cryptosporidiosis outbreak from evolving into a community-wide outbreak.
authors.affiliation: Centres for Disease Control and Prevention,Atlanta,GA,USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Cope
authors.affiliation: Centres for Disease Control and Prevention,Atlanta,GA,USA.
authors.forename: A
authors.initials: A
authors.lastname: Prosser
authors.affiliation: Ohio Department of Health,Columbus,OH,USA.
authors.forename: S
authors.initials: S
authors.lastname: Nowicki
authors.affiliation: Epidemic Intelligence Service,Centres for Disease Control and Prevention,Atlanta,GA,USA.
authors.forename: M W
authors.initials: MW
authors.lastname: Roberts
authors.affiliation: Centres for Disease Control and Prevention,Atlanta,GA,USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Roberts
authors.affiliation: Mercer County Celina City Health Department,Celina,OH,USA.
authors.forename: D
authors.initials: D
authors.lastname: Scheer
authors.affiliation: Auglaize County Health Department,Wapakoneta,OH,USA.
authors.forename: C
authors.initials: C
authors.lastname: Anderson
authors.affiliation: Auglaize County Health Department,Wapakoneta,OH,USA.
authors.forename: A
authors.initials: A
authors.lastname: Longsworth
authors.affiliation: Auglaize County Health Department,Wapakoneta,OH,USA.
authors.forename: C
authors.initials: C
authors.lastname: Parsons
authors.affiliation: Centres for Disease Control and Prevention,Atlanta,GA,USA.
authors.forename: D
authors.initials: D
authors.lastname: Goldschmidt
authors.affiliation: Centres for Disease Control and Prevention,Atlanta,GA,USA.
authors.forename: S
authors.initials: S
authors.lastname: Johnston
authors.affiliation: Centres for Disease Control and Prevention,Atlanta,GA,USA.
authors.forename: H
authors.initials: H
authors.lastname: Bishop
authors.affiliation: Centres for Disease Control and Prevention,Atlanta,GA,USA.
authors.forename: L
authors.initials: L
authors.lastname: Xiao
authors.affiliation: Centres for Disease Control and Prevention,Atlanta,GA,USA.
authors.forename: V
authors.initials: V
authors.lastname: Hill
authors.affiliation: Centres for Disease Control and Prevention,Atlanta,GA,USA.
authors.forename: M
authors.initials: M
authors.lastname: Beach
authors.affiliation: Centres for Disease Control and Prevention,Atlanta,GA,USA.
authors.forename: M C
authors.initials: MC
authors.lastname: Hlavsa
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003457:Cryptosporidiosis / Q000453:epidemiology* / Q000517:prevention & control* / Q000635:transmission; D003458:Cryptosporidium / Q000302:isolation & purification*; D018562:Disease Transmission, Infectious / Q000517:prevention & control*; D005260:Female; D005618:Fresh Water / Q000469:parasitology*; D054879:Halogenation; D006801:Humans; D007223:Infant; D017053:Infection Control / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009820:Ohio / Q000453:epidemiology; D013551:Swimming Pools; D055815:Young Adult
keywords: Cryptosporidium; outbreaks