Hepatitis A in New South Wales, Australia from consumption of oysters: the first reported outbreak.
Between 22 January and 4 April 1997, 467 hepatitis A cases were reported to the New South Wales Health Department, Australia. To identify the cause of the outbreak, we conducted a matched case-control study, and an environmental investigation. Among 66 cases and 66 postcode-matched controls, there was a strong association between illness and consumption of oysters (adjusted odds ratio 42; 95 % confidence interval 5-379). More than two-thirds of cases reported eating oysters, including one third of cases and no controls who reported eating oysters in the Wallis Lake area. A public warning was issued on 14 February, and Wallis Lake oysters were withdrawn from sale. Hepatitis A virus was subsequently identified in oyster samples taken from the lake. Hepatitis A virus poses a special risk to consumers who eat raw oysters because it can survive for long periods in estuaries and cause severe disease.
Conaty
S
S
AIDS/Infectious Diseases Branch, NSW Health Department, North Sydney, Australia.
Bird
P
P
Bell
G
G
Kraa
E
E
Grohmann
G
G
McAnulty
J M
JM
D000328:Adult; D000818:Animals; D016022:Case-Control Studies; D004196:Disease Outbreaks / Q000517:prevention & control; D005260:Female; D006506:Hepatitis A / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control; D006801:Humans; D016013:Likelihood Functions; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009517:New South Wales / Q000453:epidemiology; D016017:Odds Ratio; D010125:Ostreidae / Q000821:virology*; D012621:Seasons; D012758:Shellfish / Q000821:virology*; D014871:Water Microbiology