Guest C, Spitalny K C, Madore H P, Pray K, Dolin R, Herrmann J E, Blacklow N R
Pediatrics. 1987 Apr;79(4):559-63.
In 1984, an outbreak of gastroenteritis occurred at a school with 1,860 students in Brooklyn, NY. In a single-stage cluster sample of 375 students, 129 (34%) had illnesses that met our case definition of vomiting or diarrhea. The mean incubation period was 26 hours, and the mean illness duration was 24 hours. All case students had eaten in the cafeteria on at least one day between Nov 13 and 16, compared with 174/214 (81%) noncase students (P = 10(-8), Fisher exact test). Foods implicated were french fries (relative risk 1.7, 95% confidence limits 1.4, 2.0) and hamburgers (relative risk 1.6, 95%, confidence limits 1.2, 2.1). Two cafeteria employees had served those foods while affected by diarrhea. By a recently developed blocking enzyme-linked immunosorbent assay, six of 11 (55%) case students showed fourfold antibody increases between acute- and convalescent-phase serum samples for Snow Mountain agent, a Norwalk-like virus, compared with one of ten (10%) noncase students (P = .04, Fisher exact test). We strongly suspect, but cannot document conclusively, that the Snow Mountain agent was spread to students on a vector of hot foods contaminated by ill food handlers. Implicated foods conferred low relative risks and could only have accounted for 74% of cases of illness. The strong association between cafeteria exposure and illness, therefore, suggests that additional modes of spread occurred.
1984年，纽约布鲁克林一所拥有1860名学生的学校爆发了肠胃炎疫情。在对375名学生进行的单阶段整群抽样中，有129名（34%）学生的病症符合我们对呕吐或腹泻的病例定义。平均潜伏期为26小时，平均病程为24小时。所有病例学生在11月13日至16日期间至少有一天在自助餐厅用餐，相比之下，174/214（81%）的非病例学生也在该餐厅用餐（P = 10^(-8)，Fisher精确检验）。涉及的食物有炸薯条（相对风险1.7，95%置信区间1.4, 2.0）和汉堡包（相对风险1.6，95%置信区间1.2, 2.1）。两名自助餐厅员工在腹泻期间供应了这些食物。通过最近开发的阻断酶联免疫吸附测定法，11名病例学生中有6名（55%）在急性期和恢复期血清样本中针对雪山因子（一种诺如病毒）的抗体增加了四倍，相比之下，10名非病例学生中有1名（10%）出现这种情况（P = 0.04，Fisher精确检验）。我们强烈怀疑，但无法确凿证明，雪山因子是通过受感染食品处理人员污染的热食载体传播给学生的。涉及的食物相对风险较低，仅能解释74%的病例。因此，自助餐厅接触与疾病之间的强烈关联表明存在其他传播方式。
