title: Resurgence of field fever in a temperate country: an epidemic of leptospirosis among seasonal strawberry harvesters in Germany in 2007.
abstract: BACKGROUND
  Although leptospirosis is a reemerging zoonosis of global importance, outbreaks related to agricultural exposures are primarily situated in tropical countries. In July 2007, a suspected leptospirosis outbreak was recognized among strawberry harvesters from Eastern Europe who were working in Germany. An investigation was initiated to identify the outbreak source and the risk factors for infection.
  
  
  METHODS
  We conducted a retrospective cohort study with use of a questionnaire administered to harvesters by health authorities in Romania, Slovakia, and Poland. Collected serum samples were tested by microscopic agglutination test and immunoglobulin M enzyme-linked immunosorbent assay. A case patient was defined as a person who worked in the strawberry field during the period 5 June-8 September 2007 and had leptospirosis-compatible symptoms and either an antibody titer 1:800 and a positive immunoglobulin M enzyme-linked immunosorbent assay result (for a confirmed case) or no serological confirmation (for a suspected case). Local rodents were examined for leptospirosis.
  
  
  RESULTS
  Among 153 strawberry harvesters, we detected 13 confirmed case patients who had test results positive for antibodies against Leptospira species serogroup Grippotyphosa and 11 suspected case patients (attack rate, 16%). Risk of disease increased with each day that an individual worked in the rain with hand wounds (odds ratio, 1.1; 95% confidence interval, 1.04-1.14) and accidental rodent contact (odds ratio, 4.8; 95% confidence interval, 1.5-15.9). Leptospires of the serogroup Grippotyphosa were isolated from the kidneys of 7 (64%) of 11 voles.
  
  
  CONCLUSIONS
  This is, to our knowledge, the largest leptospirosis epidemic to occur in Germany since the 1960s. Contact between hand lesions and contaminated water or soil and infected voles was the most likely outbreak source. The unusually warm winter of 2006-2007 supported vole population growth and contributed to this resurgence of leptospirosis in Germany. Because of ongoing climate change, heightened awareness of leptospirosis in temperate regions is warranted.
authors.affiliation: Department for Infectious Disease Epidemiology, Robert Koch Institute, Free University, Veterinary Faculty, Berlin, Germany.
authors.forename: Sarika
authors.initials: S
authors.lastname: Desai
authors.forename: Ulrich
authors.initials: U
authors.lastname: van Treeck
authors.forename: Michael
authors.initials: M
authors.lastname: Lierz
authors.forename: Werner
authors.initials: W
authors.lastname: Espelage
authors.forename: Lavinia
authors.initials: L
authors.lastname: Zota
authors.forename: Anca
authors.initials: A
authors.lastname: Sarbu
authors.forename: Michal
authors.initials: M
authors.lastname: Czerwinski
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Sadkowska-Todys
authors.forename: Maria
authors.initials: M
authors.lastname: Avdicová
authors.forename: Jochen
authors.initials: J
authors.lastname: Reetz
authors.forename: Enno
authors.initials: E
authors.lastname: Luge
authors.forename: Beatriz
authors.initials: B
authors.lastname: Guerra
authors.forename: Karsten
authors.initials: K
authors.lastname: Nöckler
authors.forename: Andreas
authors.initials: A
authors.lastname: Jansen
mesh_terms: D000293:Adolescent; D000328:Adult; D000382:Agricultural Workers' Diseases / Q000453:epidemiology*; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D003411:Arvicolinae / Q000382:microbiology; D002980:Climate; D015331:Cohort Studies; D004196:Disease Outbreaks; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D007919:Leptospira / Q000302:isolation & purification; D007922:Leptospirosis / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial