title: Reemergence of recombinant vaccine-derived poliovirus outbreak in Madagascar.
abstract: BACKGROUND
  After the 2001-2002 poliomyelitis outbreak due to recombinant vaccine-derived polioviruses (VDPVs) in the Toliara province of Madagascar, another outbreak reoccurred in the same province in 2005.
  
  
  METHODS
  We conducted epidemiological and virological investigations for each polio case patient and for their contacts.
  
  
  RESULTS
  From May to August 2005, a total of 5 cases of acute flaccid paralysis were reported among unvaccinated or partially vaccinated children 2-3 years old. Type-3 or type-2 VDPV was isolated from case patients and from healthy contacts. These strains were classified into 4 recombinant lineages that showed complex mosaic genomic structures originating from different vaccine strain serotypes and probably from human enterovirus C (HEV-C) species. Genetic relatedness could be observed among these 4 lineages. Vaccination coverage of the population was very low (<50%).
  
  
  CONCLUSIONS
  The broad distribution of VDPVs in the province and their close genetic relationship indicate intense and rapid cocirculation and coevolution of the vaccine strains and of their related HEV-C strains. The occurrence of an outbreak due to VDPV 3 years after a previous outbreak indicates that a short period with low vaccination coverage is enough to create favorable conditions for the emergence of VDPV in this setting.
authors.affiliation: Unité de Virologie, Institut Pasteur de Madagascar, Madagascar. mala@pasteur.mg
authors.forename: Mala
authors.initials: M
authors.lastname: Rakoto-Andrianarivelo
authors.forename: Nicksy
authors.initials: N
authors.lastname: Gumede
authors.forename: Sophie
authors.initials: S
authors.lastname: Jegouic
authors.forename: Jean
authors.initials: J
authors.lastname: Balanant
authors.forename: Seta N
authors.initials: SN
authors.lastname: Andriamamonjy
authors.forename: Sendraharimanana
authors.initials: S
authors.lastname: Rabemanantsoa
authors.forename: Maureen
authors.initials: M
authors.lastname: Birmingham
authors.forename: Bakolalao
authors.initials: B
authors.lastname: Randriamanalina
authors.forename: Léon
authors.initials: L
authors.lastname: Nkolomoni
authors.forename: Marietjie
authors.initials: M
authors.lastname: Venter
authors.forename: Barry D
authors.initials: BD
authors.lastname: Schoub
authors.forename: Francis
authors.initials: F
authors.lastname: Delpeyroux
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Reynes
mesh_terms: D002675:Child, Preschool; D004196:Disease Outbreaks; D030015:Enterovirus C, Human / Q000235:genetics; D006801:Humans; D008270:Madagascar / Q000453:epidemiology; D008297:Male; D010802:Phylogeny; D011051:Poliomyelitis / Q000453:epidemiology* / Q000821:virology; D017955:Poliovirus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D023321:Poliovirus Vaccines / Q000009:adverse effects* / Q000302:isolation & purification; D012367:RNA, Viral / Q000235:genetics; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA; D014614:Vaccines, Synthetic / Q000009:adverse effects
chemical_list: D023321:Poliovirus Vaccines; D012367:RNA, Viral; D014614:Vaccines, Synthetic