title: A multistate outbreak of hepatitis A associated with semidried tomatoes in Australia, 2009.
abstract: BACKGROUND
  A large outbreak of hepatitis A affected individuals in several Australian states in 2009, resulting in a 2-fold increase in cases reported to state health departments compared with 2008. Two peaks of infection occurred (April-May and September-November), with surveillance data suggesting locally acquired infections from a widely distributed food product.
  
  
  METHODS
  Two case-control studies were completed. Intensive product trace-back and food sampling was undertaken. Genotyping was conducted on virus isolates from patient serum and food samples. Control measures included prophylaxis for close contacts, public health warnings, an order by the chief health officer under the Victorian Food Act 1984, and trade-level recalls on implicated batches of semidried tomatoes.
  
  
  RESULTS
  A multijurisdictional case-control study in April-May found an association between illness and consumption of semidried tomatoes (odds ratio [OR], 3.0; 95% CI 1.4-6.7). A second case-control study conducted in Victoria in October-November also implicated semidried tomatoes as being associated with illness (OR, 10.3; 95% CI, 4.7-22.7). Hepatitis A RNA was detected in 22 samples of semidried tomatoes. Hepatitis A virus genotype IB was identified in 144 of 153 (94%) patients tested from 2009, and partial sequence analysis showed complete identity with an isolate found in a sample of semidried tomatoes.
  
  
  CONCLUSIONS
  The results of both case-control studies and food testing implicated the novel vehicle of semidried tomatoes as the cause of this hepatitis A outbreak. The outbreak was extensive and sustained despite public health interventions, the design and implementation of which were complicated by limitations in food testing capability and complex supply chains.
authors.affiliation: Victorian Government Department of Health, ational Centre for Epidemiology and Population Health, College of Medicine and Biological Sciences, The Australian National University, Melbourne, Australia.
authors.forename: Ellen J
authors.initials: EJ
authors.lastname: Donnan
authors.forename: James E
authors.initials: JE
authors.lastname: Fielding
authors.forename: Joy E
authors.initials: JE
authors.lastname: Gregory
authors.forename: Karin
authors.initials: K
authors.lastname: Lalor
authors.forename: Stacey
authors.initials: S
authors.lastname: Rowe
authors.forename: Paul
authors.initials: P
authors.lastname: Goldsmith
authors.forename: Mira
authors.initials: M
authors.lastname: Antoniou
authors.forename: Kathleen E
authors.initials: KE
authors.lastname: Fullerton
authors.forename: Katrina
authors.initials: K
authors.lastname: Knope
authors.forename: Joy G
authors.initials: JG
authors.lastname: Copland
authors.forename: D Scott
authors.initials: DS
authors.lastname: Bowden
authors.forename: Samantha L
authors.initials: SL
authors.lastname: Tracy
authors.forename: Geoffrey G
authors.initials: GG
authors.lastname: Hogg
authors.forename: Agnes
authors.initials: A
authors.lastname: Tan
authors.forename: Jim
authors.initials: J
authors.lastname: Adamopoulos
authors.forename: Joanna
authors.initials: J
authors.lastname: Gaston
authors.forename: Hassan
authors.initials: H
authors.lastname: Vally
mesh_terms: D000293:Adolescent; D000328:Adult; D001315:Australia / Q000453:epidemiology; D016022:Case-Control Studies; D004196:Disease Outbreaks; D005260:Female; D005516:Food Microbiology; D057141:Food, Preserved / Q000821:virology; D005838:Genotype; D006506:Hepatitis A / Q000453:epidemiology* / Q000821:virology; D017957:Hepatitis A Virus, Human / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D018551:Solanum lycopersicum / Q000821:virology*; D008297:Male; D008875:Middle Aged; D057051:Product Recalls and Withdrawals; D012367:RNA, Viral / Q000302:isolation & purification*; D055815:Young Adult
chemical_list: D012367:RNA, Viral