title: Lessons learned during active epidemiological surveillance of Ebola and Marburg viral hemorrhagic fever epidemics in Africa.
abstract: OBJECTIVE
  To review epidemiological surveillance approaches used during Ebola and Marburg hemorrhagic fever epidemics in Africa in the past fifteen years. Overall, 26 hemorrhagic epidemic outbreaks have been registered in 12 countries; 18 caused by the Ebola virus and eight by the Marburg virus. About 2551 cases have been reported, among which 268 were health workers (9,3%).
  
  
  METHODS
  Based on articles and epidemic management reports, this review analyses surveillance approaches, route of introduction of the virus into the population (urban and rural), the collaboration between the human health sector and the wildlife sector and factors that have affected epidemic management.
  
  
  RESULTS
  Several factors affecting the epidemiological surveillance during Ebola and Marburg viruses hemorrhagic epidemics have been observed. During epidemics in rural settings, outbreak investigations have shown multiple introductions of the virus into the human population through wildlife. In contrast, during epidemics in urban settings a single introduction of the virus in the community was responsible for the epidemic. Active surveillance is key to containing outbreaks of Ebola and Marburg viruses
  
  
  CONCLUSIONS
  Collaboration with those in charge of the conservation of wildlife is essential for the early detection of viral hemorrhagic fever epidemics. Hemorrhagic fever epidemics caused by Ebola and Marburg viruses are occurring more and more frequently in Sub-Saharan Africa and only an adapted epidemiological surveillance system will allow for early detection and effective response.
authors.affiliation: WHO, Regional office for Africa, Brazzaville, Congo. allarangary@gw.afro.who.int
authors.forename: Yokouide
authors.initials: Y
authors.lastname: Allaranga
authors.forename: Mamadou Lamine
authors.initials: ML
authors.lastname: Kone
authors.forename: Pierre
authors.initials: P
authors.lastname: Formenty
authors.forename: Francois
authors.initials: F
authors.lastname: Libama
authors.forename: Paul
authors.initials: P
authors.lastname: Boumandouki
authors.forename: Celia J I
authors.initials: CJ
authors.lastname: Woodfill
authors.forename: Idrissa
authors.initials: I
authors.lastname: Sow
authors.forename: Sambe
authors.initials: S
authors.lastname: Duale
authors.forename: Wondimagegnehu
authors.initials: W
authors.lastname: Alemu
authors.forename: Adamou
authors.initials: A
authors.lastname: Yada
mesh_terms: D000349:Africa / Q000453:epidemiology; D000818:Animals; D016358:Contact Tracing; D018563:Disease Notification; D029043:Ebolavirus / Q000302:isolation & purification*; D058872:Epidemics; D019142:Hemorrhagic Fever, Ebola / Q000175:diagnosis / Q000453:epidemiology* / Q000635:transmission / Q000821:virology; D006801:Humans; D008379:Marburg Virus Disease / Q000175:diagnosis / Q000453:epidemiology* / Q000635:transmission / Q000821:virology; D029024:Marburgvirus / Q000302:isolation & purification; D011159:Population Surveillance