title: Large outbreak of Cryptosporidium hominis infection transmitted through the public water supply, Sweden.
abstract: In November 2010, ≈27,000 (≈45%) inhabitants of Östersund, Sweden, were affected by a waterborne outbreak of cryptosporidiosis. The outbreak was characterized by a rapid onset and high attack rate, especially among young and middle-aged persons. Young age, number of infected family members, amount of water consumed daily, and gluten intolerance were identified as risk factors for acquiring cryptosporidiosis. Also, chronic intestinal disease and young age were significantly associated with prolonged diarrhea. Identification of Cryptosporidium hominis subtype IbA10G2 in human and environmental samples and consistently low numbers of oocysts in drinking water confirmed insufficient reduction of parasites by the municipal water treatment plant. The current outbreak shows that use of inadequate microbial barriers at water treatment plants can have serious consequences for public health. This risk can be minimized by optimizing control of raw water quality and employing multiple barriers that remove or inactivate all groups of pathogens.
authors.forename: Micael
authors.initials: M
authors.lastname: Widerström
authors.forename: Caroline
authors.initials: C
authors.lastname: Schönning
authors.forename: Mikael
authors.initials: M
authors.lastname: Lilja
authors.forename: Marianne
authors.initials: M
authors.lastname: Lebbad
authors.forename: Thomas
authors.initials: T
authors.lastname: Ljung
authors.forename: Görel
authors.initials: G
authors.lastname: Allestam
authors.forename: Martin
authors.initials: M
authors.lastname: Ferm
authors.forename: Britta
authors.initials: B
authors.lastname: Björkholm
authors.forename: Anette
authors.initials: A
authors.lastname: Hansen
authors.forename: Jari
authors.initials: J
authors.lastname: Hiltula
authors.forename: Jonas
authors.initials: J
authors.lastname: Långmark
authors.forename: Margareta
authors.initials: M
authors.lastname: Löfdahl
authors.forename: Maria
authors.initials: M
authors.lastname: Omberg
authors.forename: Christina
authors.initials: C
authors.lastname: Reuterwall
authors.forename: Eva
authors.initials: E
authors.lastname: Samuelsson
authors.forename: Katarina
authors.initials: K
authors.lastname: Widgren
authors.forename: Anders
authors.initials: A
authors.lastname: Wallensten
authors.forename: Johan
authors.initials: J
authors.lastname: Lindh
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D003457:Cryptosporidiosis / Q000453:epidemiology* / Q000382:microbiology; D003458:Cryptosporidium / Q000302:isolation & purification*; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D013548:Sweden / Q000453:epidemiology; D014867:Water; D014871:Water Microbiology; D018508:Water Purification / Q000379:methods; D014881:Water Supply; D055815:Young Adult
chemical_list: D014867:Water
keywords: Cryptosporidium hominis infection; cryptosporidiosis/epidemiology; cryptosporidiosis/prevention and control; cryptosporidiosis/transmission; diarrhea; disease outbreaks; drinking water; molecular typing; questionnaires; risk factors; waste management, parasites; water microbiology; water supply; waterborne infections