title: A large food-borne outbreak of group A streptococcal pharyngitis in an industrial plant: potential for deliberate contamination.
abstract: Contamination of food with streptococci could present with unusual outbreaks that may be difficult to recognize in the early stages. This is demonstrated in a large food-borne outbreak of streptococcal pharyngitis that occurred in 2003 in a factory in Israel. The outbreak was reported to the public health services on July 2 and an epidemiologic investigation was initiated. Cases and controls were interviewed and throat swabs were taken. An estimated 212 cases occurred within the first 4 days, the peak occurring on the second day. There was a wave of secondary cases during an additional 11 days. The early signs were of a respiratory illness including sore throat, weakness and fever, with high absenteeism rates suggesting a respiratory illness. As part of a case-control study, cases and controls were interviewed and throat swabs taken. Illness was significantly associated with consumption of egg-mayonnaise salad (odds ratio 4.2, 95% confidence interval 1.4-12.6), suggesting an incubation period of 12-96 hours. The initial respiratory signs of food-borne streptococcal pharyngitis outbreaks could delay the identification of the vehicle of transmission. This could be particularly problematic in the event of deliberate contamination.
authors.affiliation: Public Health Services, Ministry of Health,Jerusalem, Israel.
authors.forename: Dorit Nitzan
authors.initials: DN
authors.lastname: Kaluski
authors.forename: Estrella
authors.initials: E
authors.lastname: Barak
authors.forename: Zalman
authors.initials: Z
authors.lastname: Kaufman
authors.forename: Lea
authors.initials: L
authors.lastname: Valinsky
authors.forename: Esther
authors.initials: E
authors.lastname: Marva
authors.forename: Zina
authors.initials: Z
authors.lastname: Korenman
authors.forename: Zeev
authors.initials: Z
authors.lastname: Gorodnitzki
authors.forename: Ruth
authors.initials: R
authors.lastname: Yishai
authors.forename: Deborah
authors.initials: D
authors.lastname: Koltai
authors.forename: Alex
authors.initials: A
authors.lastname: Leventhal
authors.forename: Shimon
authors.initials: S
authors.lastname: Levine
authors.forename: Ofra
authors.initials: O
authors.lastname: Havkin
authors.forename: Manfred S
authors.initials: MS
authors.lastname: Green
mesh_terms: D023482:Bioterrorism; D016022:Case-Control Studies; D004196:Disease Outbreaks; D004531:Eggs / Q000382:microbiology; D004812:Epidemiologic Methods; D005516:Food Microbiology; D006801:Humans; D007221:Industry; D007557:Israel / Q000453:epidemiology; D009784:Occupational Diseases / Q000453:epidemiology* / Q000382:microbiology*; D010612:Pharyngitis / Q000453:epidemiology* / Q000382:microbiology*; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D013297:Streptococcus pyogenes / Q000302:isolation & purification*