An outbreak of hepatitis A associated with green onions

J Infect Dis. 2001 Apr 15;183(8):1273-6. doi: 10.1086/319688. Epub 2001 Mar 26.


Forty-three cases of serologically confirmed hepatitis A occurred among individuals who ate at restaurant A in Ohio in 1998. Serum samples from all restaurant A employees who worked during the exposure period were negative for IgM antibodies to hepatitis A virus (HAV). A matched case-control study determined that foods containing green onions, which were eaten by 38 (95%) of 40 case patients compared with 30 (50%) of 60 control subjects, were associated with illness (matched odds ratio, 12.7; 95% confidence interval, 2.6-60.8). Genetic sequences of viral isolates from 14 case patients were identical to each other and to those of viral isolates from 3 patients with cases of hepatitis A acquired in Mexico. Although the implicated green onions, which could have come from one of 2 Mexican farms or from a Californian farm, were widely distributed, no additional green onion-associated cases were detected. More sensitive methods are needed to detect foodborne hepatitis A. A better understanding of how HAV might contaminate raw produce would aid in developing prevention strategies.

Publication types

  • Comparative Study

MeSH terms

  • California
  • Case-Control Studies
  • Disease Outbreaks*
  • Food Microbiology*
  • Hepatitis A / epidemiology*
  • Hepatitis A / transmission
  • Hepatitis A Antibodies
  • Hepatitis Antibodies / blood
  • Hepatovirus / classification
  • Hepatovirus / genetics
  • Hepatovirus / isolation & purification*
  • Humans
  • Mexico
  • Odds Ratio
  • Ohio / epidemiology
  • Onions / microbiology*
  • Phylogeny
  • Restaurants*


  • Hepatitis A Antibodies
  • Hepatitis Antibodies