title: Cryptosporidium parvum Caused a Large Outbreak Linked to Frisée Salad in Finland, 2012.
abstract: Over 250 individuals fell ill in five outbreaks caused by Cryptosporidium parvum in Finland, October-November 2012. The cases were connected by lunch meals at restaurants in four different cities. In two outbreaks, the same C. parvumIIdA17G1 subtype was found in patients' stool samples which supports a single source of infection. Frisée salad was the only common food item served at the restaurants, and consumption of lunch salad containing the frisée salad was associated with the illness. Lunch customers who responded that they had eaten lunch salad were three times more likely to have become ill than those who had not answered whether they had eaten the salad or not (RR 2.66; 95% Cl 1.02-6.9, P-value <0.01). Cryptosporidiosis should be considered as a causal agent in long-lasting watery diarrhoea combined with abdominal cramps, and clinical samples should be tested for Cryptosporidium at the same time bacteria and viruses are tested. Measures to prevent contamination of 'ready-to-eat vegetables' with Cryptosporidium oocysts and methods to test frozen food samples should be developed.
authors: Food Safety Department, Environment Centre, Helsinki, Finland.
authors: R
authors: R
authors: Åberg
authors: Food Safety Department, Environment Centre, Helsinki, Finland.
authors: M
authors: M
authors: Sjöman
authors: Social and Health Services, Environmental Health, Espoo, Finland.
authors: K
authors: K
authors: Hemminki
authors: Social and Health Services, Environmental Health, Espoo, Finland.
authors: A
authors: A
authors: Pirnes
authors: Health Services, Tampere, Finland.
authors: S
authors: S
authors: Räsänen
authors: Clinical Microbiology, Helsinki University Central Hospital, Hospital District of Helsinki and Uusimaa, Laboratory Services, HUSLAB, Helsinki, Finland.
authors: A
authors: A
authors: Kalanti
authors: Veterinary Bacteriology Unit, Finnish Food Safety Authority Evira, Kuopio, Finland.
authors: T
authors: T
authors: Pohjanvirta
authors: European Union Reference Laboratory for Parasites, Istituto Superiore di Sanità, Rome, Italy.
authors: S M
authors: SM
authors: Caccio
authors: Food Hygiene Unit, Finnish Food Safety Authority Evira, Helsinki, Finland.
authors: A
authors: A
authors: Pihlajasaari
authors: Department for Infectious Disease Surveillance and Control, National Institute for Health and Welfare, Helsinki, Finland.
authors: S
authors: S
authors: Toikkanen
authors: Department for Infectious Disease Surveillance and Control, National Institute for Health and Welfare, Helsinki, Finland.
authors: S
authors: S
authors: Huusko
authors: Department for Infectious Disease Surveillance and Control, National Institute for Health and Welfare, Helsinki, Finland.
authors: R
authors: R
authors: Rimhanen-Finne
mesh_terms: D003457:Cryptosporidiosis / Q000453:epidemiology / Q000469:parasitology*; D016785:Cryptosporidium parvum; D004196:Disease Outbreaks; D005243:Feces / Q000469:parasitology; D005387:Finland / Q000453:epidemiology; D016266:Food Parasitology; D006801:Humans; D014675:Vegetables / Q000469:parasitology*
keywords: Cryptosporidium; lunch salad; outbreak