title: Cluster of acute hemorrhagic appendicitis among high school students in Wuhan, China.
abstract: BACKGROUND
  Features of a cluster of acute appendicitis that occurred among a high school student population in China were investigated.
  
  
  METHODS
  Epidemiologic data, medical records, and histologic slides of resected appendices were examined.
  
  
  RESULTS
  During a period between April 10, 1997, and June 11, 1997, 11 cases occurred in a high school, with 10 cases among 290 students enrolled at the time. From the end of the initial cluster until June, 2000, 20 additional cases were encountered. Female cases (6.5%) are more frequent than male cases (1.9%). There was a clustering pattern. Many patients had a history of mutual contact before the onset of symptoms. Pathologically, the resected appendices exhibited diffuse or focal hemorrhages in the lamina propria or within hyperplastic lymphoid follicles, and infiltration by eosinophils and by lymphocytes. Appendical tissues were examined using immunohistochemistry, but no etiologic agent was identified.
  
  
  CONCLUSIONS
  This cluster of acute appendicitis represented a special kind of appendicitis, with features of an infectious disease in epidemiology.
authors.affiliation: Department of Epidemiology, School of Public Health and the Key Laboratory of Virology, Ministry of Education of China, Wuhan University, 115 Donghu Rd, Wuchang, Wuhan 430071, Hubei Province, China; Department of Pathology and WHO Collaborating Center for Tropical Diseases, University of Texas Medical Branch, Galveston, TX, USA. guoyius@yahoo.co
authors.forename: Yi
authors.initials: Y
authors.lastname: Guo
authors.forename: Shu-Yuan
authors.initials: SY
authors.lastname: Xiao
authors.forename: Hong
authors.initials: H
authors.lastname: Yan
authors.forename: Ning-Dong
authors.initials: ND
authors.lastname: Sun
authors.forename: Ming-Sen
authors.initials: MS
authors.lastname: Jiang
authors.forename: Dong-Ying
authors.initials: DY
authors.lastname: Liu
mesh_terms: D000328:Adult; D001064:Appendicitis / Q000150:complications / Q000453:epidemiology* / Q000473:pathology; D002681:China / Q000453:epidemiology; D004196:Disease Outbreaks; D005260:Female; D006470:Hemorrhage / Q000209:etiology / Q000473:pathology; D006801:Humans; D008297:Male; D012574:Schools; D017678:Sex Distribution