title: [Tuberculosis outbreak in a primary school: description and reflections on the value of gastric juice in the management of micro-epidemics].
abstract: OBJECTIVE
  To describe a tuberculosis outbreak in a primary school arising from a secondary case.
  
  
  METHODS
  Contact study and clinical study of exposed patients. Chest x-ray, gastric aspirate processing, and clinical evaluation of all children with a positive tuberculin skin test (TST) were recorded. Differential diagnosis between tuberculosis disease (TB) and latent tuberculosis infection (LTI).
  
  
  RESULTS
  Two groups were identified: one of higher exposure to the index case (> 6 hours/day, for 3 months; n=17 children) and one of sporadic exposure (< 6 hours/day; n=82 children). Clinical or bacteriological criteria for diagnosing TB were seen in 6 out of 17 (35%) highly exposed children. Four of them had clinical or radiological criteria. The other two children were asymptomatic and had a normal chest X ray, but had a positive gastric aspirate for M. tuberculosis. The overall infection rate (TB+LTI) was 94%. One child out of 82 (1.2%) sporadically exposed children had radiological criteria for TB. Staff latent infection rate was 15%. Apart from the index case, there were no other tuberculosis cases among the staff. Relative risk (RR) of exposed children was 28.5 (95% CI: 3-250).
  
  
  CONCLUSIONS
  Prolonged exposure to a baciliferous patient may infect almost every child exposed in closed groups. It can also cause a high attack rate. In this scenario, routine gastric aspirate may be considered for all children with a positive TST. It may identify early subclinical TB with an increased probability of isolating the M. tuberculosis. The potential benefit of this isolation may reach the entire cohort.
authors.affiliation: Servicio de Pediatría, Hospital Infanta Sofía, San Sebastián de Reyes, Madrid, España. alfredotagarro@hotmail.com
authors.forename: Alfredo
authors.initials: A
authors.lastname: Tagarro
authors.forename: Susana
authors.initials: S
authors.lastname: Jiménez
authors.forename: Aida
authors.initials: A
authors.lastname: Sánchez
authors.forename: Alicia
authors.initials: A
authors.lastname: Arroyo
authors.forename: Javier
authors.initials: J
authors.lastname: Aracil
authors.forename: Alfonso
authors.initials: A
authors.lastname: Cañete
mesh_terms: D000328:Adult; D002675:Child, Preschool; D016358:Contact Tracing; D004196:Disease Outbreaks; D004314:Down Syndrome / Q000150:complications; D042241:Early Diagnosis; D004781:Environmental Exposure; D005178:Faculty; D005260:Female; D005750:Gastric Juice / Q000382:microbiology*; D006801:Humans; D055985:Latent Tuberculosis / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000453:epidemiology; D008297:Male; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D011859:Radiography; D012306:Risk; D012574:Schools; D013030:Spain / Q000453:epidemiology; D014374:Tuberculin Test; D014376:Tuberculosis / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission