title: [Outbreak of shigellosis in a lower-class district].
abstract: BACKGROUND
  The outbreaks of Shigella sonnei in our environment frequently involve day care centers and elementary schools. An outbreak of shigellosis in a lower-class district is reported. The purpose of this study is that of pinpointing the center of infection, the means of contagion, the characteristics of those infected and of assessing the suitability of the measures taken.
  
  
  METHODS
  For monitoring the outbreak over time, a combined observational timeline study was conducted within a territory the bounds of which were marked by means of the conventional epidemiological monitoring variables (time, place and individual). The infectivity of the center of infection (contagion rate) is analyzed by age, gender and school; rate ratio and percentage attributable thereto.
  
  
  RESULTS
  On a time-related basis, the outbreak in question started on week 46/97 and ended on week 8/98. This outbreak involved 218 individuals (110 males and 108 females) totaling 5.46% of the district. The highest frequency was found among the 0-4 age group (43.6%), 29.4% in day care (70.32% contagion rate) with a relative risk of 3.9 (95% CI: 2.57-5.93) and 74.36% attributable percentage. The rate ratio between day care and the schools in the district in question is 5.62 (95% CI: 4.33-7.31). Stool cultures were taken and analyzed in 84 cases (38.5%), Shigella sonnei being detected in 38 cases (17.4%). Antibacterial treatment (amoxicillin-clavulan) was set out and individual and group health and safety measures were employed.
  
  
  CONCLUSIONS
  The long communicability period and the small number of viable microorganisms necessary for causing this disease fostered its being passed on from one person to another at school and in the home. The measures employed effectively confined the contagion of the infectious agent at the schools.
authors.affiliation: Secciones de Epidemiología y laboratorio, Centro de Salud Publica de Valencia. joseluis.chover@sanidad.m400.gva.es
authors.forename: J L
authors.initials: JL
authors.lastname: Chover Lara
authors.forename: A
authors.initials: A
authors.lastname: Salazar Cifre
authors.forename: M
authors.initials: M
authors.lastname: Gallego Cruz
authors.forename: M L
authors.initials: ML
authors.lastname: Camaró Sala
authors.forename: C
authors.initials: C
authors.lastname: Segarra Martínez
authors.forename: M C
authors.initials: MC
authors.lastname: Peñalver Blasco
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks; D004405:Dysentery, Bacillary / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D012923:Social Class; D013030:Spain / Q000453:epidemiology; D013997:Time Factors