A foodborn outbreak of beta hemolitic streptococcal sore throat occurred in Tokyo, in an early July, 1983, among people who had attended at a lecture meeting sponsored by a company.
Questionnaire information was obtained on 890 persons or 97.6% of the attendees, 583 (65.5%) of whom became ill with a sore throat.
Other major symptomes and signs of the patients were fever (85.4%), malaise (83.2%), headache (65.4%) and tender cervical adenopathy (61.1%). Ninety-eight or 18.1% had diarrhoea, 52 or 9.4% had abdominal pain, and 2.7% experienced vomiting. Skin rash was reported by 13 or 2.3%. There were no fetal cases.
The median incubation time was estimated to be 37 hours.
Twenty-seven of 74 (36.5%) throat culture, 24 of 49 (49.0%) from ill persons and 3 of 25 (12%) from healthy persons, were positive for group A beta hemolitic streptococci. All of the isolates were classified as T type 13 and M untypable.
Among ill persons, significant rise of serum anti-streptolysin 0, anty-hyaluronidase and anti-NADase titers was observed in convalescence.
Food preferences and illness rates incriminated the egg-sandwich catered at the meeting as the vehicle of the infection. Further support for this incrimination was provided by the following facts;(1) throat cultures of two food handlers who cooked the sandwiches were positive for the outbreak strain, and (2) some attendees and family members who ate the left-over sandwiches also had become ill with a short incubation period, and the outbreak strain was recovered from their throat.
View full abstract