title: Outbreak of Campylobacteriosis Following a Dairy Farm Visit: Confirmation by Genotyping.
abstract: In April-May 2014, an outbreak of campylobacteriosis occurred after a preschool visit to a dairy farm in the South Western part of Sweden. During the visit, a meal, including unpasteurized milk, was served. A retrospective cohort study using a web-based questionnaire was performed among the participants (n = 30) of the farm visit. A total of 24 of the 30 (80%) cohort members completed the questionnaire. Eleven cases were identified, and Campylobacter jejuni was isolated from eight of them. Seven of the cases were 2- to 7-year-old children. We found the highest attack rates among those who usually drink milk (45%) and those who consumed unpasteurized milk during the farm visit (42%). No cases were unexposed (risk ratio incalculable). As result of the farm investigation, Campylobacter was isolated from cattle on the farm. Genotyping with pulsed-field gel electrophoresis and whole genome sequencing confirmed that human and cattle isolates of C. jejuni belonged to one cluster. Thus, cattle on the farm are considered the source of infection, and the most likely vehicle of transmission was contaminated unpasteurized milk. We recommend consumption of heat-treated milk only and increased awareness of the risk of consuming unpasteurized milk.
authors.affiliation: 1 National Veterinary Institute , Uppsala, Sweden .
authors.forename: Elina
authors.initials: E
authors.lastname: Lahti
authors.affiliation: 2 The Public Health Agency of Sweden , Solna, Sweden .|3 European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control (ECDC) , Stockholm, Sweden .
authors.forename: Moa
authors.initials: M
authors.lastname: Rehn
authors.affiliation: 4 Smittskydd Västra Götaland , Södra Älvsborgs Sjukhus, Borås, Sweden .
authors.forename: Gunilla
authors.initials: G
authors.lastname: Ockborn
authors.affiliation: 1 National Veterinary Institute , Uppsala, Sweden .
authors.forename: Ingrid
authors.initials: I
authors.lastname: Hansson
authors.affiliation: 1 National Veterinary Institute , Uppsala, Sweden .
authors.forename: Joakim
authors.initials: J
authors.lastname: Ågren
authors.affiliation: 1 National Veterinary Institute , Uppsala, Sweden .
authors.forename: Eva Olsson
authors.initials: EO
authors.lastname: Engvall
authors.affiliation: 2 The Public Health Agency of Sweden , Solna, Sweden .
authors.forename: Cecilia
authors.initials: C
authors.lastname: Jernberg
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D002169:Campylobacter Infections / Q000453:epidemiology*; D016123:Campylobacter jejuni / Q000235:genetics / Q000302:isolation & purification; D002417:Cattle / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D003612:Dairying; D004196:Disease Outbreaks; D000072480:Farms; D005260:Female; D005506:Food Contamination; D005516:Food Microbiology; D005517:Foodborne Diseases / Q000453:epidemiology* / Q000382:microbiology; D060005:Genotyping Techniques; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D008892:Milk / Q000382:microbiology; D061352:Pasteurization; D012189:Retrospective Studies; D013334:Students; D013548:Sweden; D055815:Young Adult
keywords: Campylobacter; cattle; farm visit; genotyping; milk; outbreak