title: The spread of influenza A(H1N1)pdm09 virus in Madagascar described by a sentinel surveillance network.
abstract: BACKGROUND
  The influenza A(H1N1)pdm09 virus has been a challenge for public health surveillance systems in all countries. In Antananarivo, the first imported case was reported on August 12, 2009. This work describes the spread of A(H1N1)pdm09 in Madagascar.
  
  
  METHODS
  The diffusion of influenza A(H1N1)pdm09 in Madagascar was explored using notification data from a sentinel network. Clinical data were charted to identify peaks at each sentinel site and virological data was used to confirm viral circulation.
  
  
  RESULTS
  From August 1, 2009 to February 28, 2010, 7,427 patients with influenza-like illness were reported. Most patients were aged 7 to 14 years. Laboratory tests confirmed infection with A(H1N1)pdm09 in 237 (33.2%) of 750 specimens. The incidence of patients differed between regions. By determining the epidemic peaks we traced the diffusion of the epidemic through locations and time in Madagascar. The first peak was detected during the epidemiological week 47-2009 in Antananarivo and the last one occurred in week 07-2010 in Tsiroanomandidy.
  
  
  CONCLUSIONS
  Sentinel surveillance data can be used for describing epidemic trends, facilitating the development of interventions at the local level to mitigate disease spread and impact.
authors.affiliation: Epidemiologic Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar.
authors.forename: Soatiana
authors.initials: S
authors.lastname: Rajatonirina
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Heraud
authors.forename: Arnaud
authors.initials: A
authors.lastname: Orelle
authors.forename: Laurence
authors.initials: L
authors.lastname: Randrianasolo
authors.forename: Norosoa
authors.initials: N
authors.lastname: Razanajatovo
authors.forename: Yolande Raoelina
authors.initials: YR
authors.lastname: Rajaona
authors.forename: Armand Eugène
authors.initials: AE
authors.lastname: Randrianarivo-Solofoniaina
authors.forename: Fanjasoa
authors.initials: F
authors.lastname: Rakotomanana
authors.forename: Vincent
authors.initials: V
authors.lastname: Richard
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks; D058872:Epidemics; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology*; D008270:Madagascar / Q000453:epidemiology; D008297:Male; D062486:Public Health Surveillance / Q000379:methods; D018571:Sentinel Surveillance; D055815:Young Adult