title: Outbreak of Yersinia pseudotuberculosis O:1 infection associated with raw milk consumption, Finland, spring 2014.
abstract: In March 2014, a Yersinia pseudotuberculosis (YP) outbreak was detected by a municipal authority in southern Finland. We conducted epidemiological, microbiological and traceback investigations to identify the source. We defined a case as a person with YP infection notified to the National Infectious Disease Registry between February and April 2014, or their household member, with abdominal pain and fever≥38 °C or erythema nodosum. Healthy household members were used as household-matched controls. We identified 43 cases and 50 controls. The illness was strongly associated with the consumption of raw milk from a single producer. The odds ratio of illness increased with the amount of raw milk consumed. Also previously healthy adults became infected by consuming raw milk. Identical YP strains were identified from cases' stool samples, raw milk sampled from a case's refrigerator and from the milk filter at the producer's farm. The producer fulfilled the legal requirements for raw milk production and voluntarily recalled the raw milk and stopped its production. We advised consumers to heat the raw milk to 72 °C for 15 s. Current legislation for raw milk producers should be reviewed and public awareness of health risks linked to raw milk consumption should be increased.
authors.affiliation: National Institute for Health and Welfare (THL), Department of Infectious Diseases Surveillance and Control, Helsinki, Finland.
authors.forename: Triin
authors.initials: T
authors.lastname: Pärn
authors.forename: Saija
authors.initials: S
authors.lastname: Hallanvuo
authors.forename: Saara
authors.initials: S
authors.lastname: Salmenlinna
authors.forename: Annika
authors.initials: A
authors.lastname: Pihlajasaari
authors.forename: Seija
authors.initials: S
authors.lastname: Heikkinen
authors.forename: Hanna
authors.initials: H
authors.lastname: Telkki-Nykänen
authors.forename: Marjaana
authors.initials: M
authors.lastname: Hakkinen
authors.forename: Jukka
authors.initials: J
authors.lastname: Ollgren
authors.forename: Sari
authors.initials: S
authors.lastname: Huusko
authors.forename: Ruska
authors.initials: R
authors.lastname: Rimhanen-Finne
mesh_terms: D000328:Adult; D000818:Animals; D016022:Case-Control Studies; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D005387:Finland / Q000453:epidemiology; D005511:Food Handling; D005516:Food Microbiology; D006801:Humans; D008297:Male; D008892:Milk / Q000382:microbiology*; D016017:Odds Ratio; D012703:Serotyping / Q000379:methods; D020080:Tandem Repeat Sequences; D015011:Yersinia pseudotuberculosis / Q000302:isolation & purification*; D015012:Yersinia pseudotuberculosis Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000635:transmission
keywords: Finland; Yersinia pseudotuberculosis; outbreaks; raw milk