title: Circulating vaccine-derived polioviruses in the Extreme North region of Cameroon.
abstract: BACKGROUND
  The World Health Organization (WHO) poliovirus eradication program includes careful surveillance of acute-flaccid paralysis (AFP) and mass and routine immunization with oral polio vaccine (OPV). In populations with low vaccine coverage, the live-attenuated Sabin strains, OPV types 1, 2 and 3, can evolve into virulent vaccine-derived polioviruses (VDPVs) and circulate in the community. Until recently, circulating VDPVs (cVDPVs) had not been reported in Cameroon despite the fact that VDPV2 outbreaks have occurred in nearby countries.
  
  
  OBJECTIVE
  This study aimed to characterize virus isolates from four AFP patients infected with cVDPV2 in the Extreme North region of Cameroon in 2013.
  
  
  METHODS
  The complete VP1 region of the four VDPV strains was sequenced and the relationships with cVDPVs from neighboring countries were investigated.
  
  
  RESULTS
  All four patients were infected by cVDPV2 strains showing 1.2-2.0% nucleotide difference compared to the reference Sabin 2 VP1 sequence. Phylogenetic analysis indicated that the VDPV strains were genetically linked to cVDPV2 lineages of the recent Chad cVDPV2 outbreak.
  
  
  CONCLUSIONS
  The circulation of pathogenic VDPVs suggests that there are localized immunization gaps in some districts like Makary, Mada and Kolofata in Cameroon. To avoid poliomyelitis outbreaks in Cameroon, especially in the districts close to neighboring countries with ongoing cVDPV outbreaks, high polio vaccine coverage is essential.
authors.affiliation: Centre Pasteur of Cameroon, P.O. Box 1274, Yaoundé, Cameroon.
authors.forename: Marie Claire
authors.initials: MC
authors.lastname: Endegue-Zanga
authors.affiliation: Centre Pasteur of Cameroon, P.O. Box 1274, Yaoundé, Cameroon.
authors.forename: Serge Alain
authors.initials: SA
authors.lastname: Sadeuh-Mba
authors.affiliation: Division of Viral and Rickettsial Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Jane
authors.initials: J
authors.lastname: Iber
authors.affiliation: Division of Viral and Rickettsial Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Cara
authors.initials: C
authors.lastname: Burns
authors.affiliation: WHO Cameroon Country Office, P.O. Box 155, Yaoundé, Cameroon.
authors.forename: Marcellin
authors.initials: M
authors.lastname: Nimpa-Mengouo
authors.affiliation: Centre Pasteur of Cameroon, P.O. Box 1274, Yaoundé, Cameroon.
authors.forename: Maurice
authors.initials: M
authors.lastname: Demanou
authors.affiliation: Centre Pasteur of Cameroon, P.O. Box 1274, Yaoundé, Cameroon.
authors.forename: Guy
authors.initials: G
authors.lastname: Vernet
authors.affiliation: The University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon.
authors.forename: François-Xavier
authors.initials: FX
authors.lastname: Etoa
authors.affiliation: Centre Pasteur of Cameroon, P.O. Box 1274, Yaoundé, Cameroon. Electronic address: njouom@pasteur-yaounde.org.
authors.forename: Richard
authors.initials: R
authors.lastname: Njouom
mesh_terms: D000293:Adolescent; D000328:Adult; D002163:Cameroon / Q000453:epidemiology; D036022:Capsid Proteins / Q000235:genetics; D002648:Child; D005260:Female; D005843:Geography; D006801:Humans; D008297:Male; D010802:Phylogeny; D011051:Poliomyelitis / Q000453:epidemiology* / Q000517:prevention & control / Q000821:virology*; D017955:Poliovirus / Q000145:classification / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D023321:Poliovirus Vaccines / Q000009:adverse effects* / Q000235:genetics; D055815:Young Adult
chemical_list: D036022:Capsid Proteins; D023321:Poliovirus Vaccines
keywords: Acute-flaccid paralysis; Cameroon; Poliomyelitis; Vaccine-derived poliovirus