AN OUTBREAK OF ILLNESS AMONG SCHOOLCHILDREN IN LONDON - TOXIC POISONING NOT MASS HYSTERIA

Study objective - To determine the cause of an outbreak of acute gastr ointestinal illness that occurred shortly after lunch in children atte nding a school in London, UK. Design - A questionnaire survey of child ren at the affected school was carried out on the day after the incide nt. Microbiological, environmental, and toxicological investigations w ere also undertaken. Setting - A school in London, UK. Participants - Altogether 374/468 (80%) of the children who had eaten lunch at the sc hool on the day of the incident completed a questionnaire. Main result s - There was a significant association between illness and the consum ption of raw cucumber (relative risk = 6.1; 95% confidence interval 2. 2, 16). Microbiological investigation of the foods served at lunch did not show any pathogens and toxicological investigations suggested tha t the cucumbers were contaminated by a pesticide. Conclusions - Althou gh the outbreak displayed several typical features of mass psychogenic illness, the most probable cause was a toxic chemical present in cucu mber served at lunch. Those responsible for investigating outbreaks of illness should be aware of the possible toxicological causes and the appropriate modes of investigation. They should be wary of too readily attributing a psychogenic cause to unusual outbreaks of acute illness in schoolchildren.