Isolation of recombinant type 2 vaccine-derived poliovirus (VDPV) from a Nigerian child.
A type 2 vaccine-derived poliovirus (VDPV), differing from Sabin 2 at 2.5% (22/903) of VP1 nucleotide (nt) positions, was isolated from an incompletely immunized 21-month-old Nigerian child who developed acute flaccid paralysis in 2002. Sequences upstream of nt position 620 (within the 5'-untranslated region [5'-UTR]) and downstream of nt position 5840 (in the 3C(pro) region) were derived from species C enteroviruses unrelated to the oral poliovirus vaccine (OPV) strains. The two substitutions associated with the attenuated phenotype had either recombined out (A(481)-->G in the 5'-UTR) or reverted (Ile(143)-->Thr in VP1). The VDPV isolate had lost the temperature sensitive phenotype of Sabin 2 and it was antigenically distinct from the parental OPV strain, having amino acid substitutions in or near neutralizing antigenic sites 1 and 3. The date of the initiating OPV dose, calculated from the number of synonymous substitutions in the capsid region, was estimated to be approximately 16 to 18 months before onset of paralysis, a finding inconsistent with the most recent mass OPV campaign (conducted 12 days before onset of paralysis) as being the source of infection. Although no related type 2 VDPVs were detected in Nigeria or elsewhere, the VDPV was found in an area where conditions favor VDPV emergence and spread.
Adu
Festus
F
National Poliovirus Laboratory, Department of Virology, College of Medicine, University of Ibadan, UCH, Ibadan, Oyo State, Nigeria.
Iber
Jane
J
Bukbuk
David
D
Gumede
Nicksy
N
Yang
Su-Ju
SJ
Jorba
Jaume
J
Campagnoli
Ray
R
Sule
Waidi Folorunso
WF
Yang
Chen-Fu
CF
Burns
Cara
C
Pallansch
Mark
M
Harry
Tekena
T
Kew
Olen
O
D020121:5' Untranslated Regions / Q000032:analysis; D036022:Capsid Proteins / Q000235:genetics* / Q000276:immunology; D005243:Feces / Q000821:virology; D016679:Genome, Viral; D006801:Humans; D007223:Infant; D008297:Male; D009549:Nigeria; D011051:Poliomyelitis / Q000517:prevention & control / Q000821:virology*; D017955:Poliovirus / Q000235:genetics / Q000302:isolation & purification*; D011055:Poliovirus Vaccine, Oral / Q000008:administration & dosage / Q000009:adverse effects*; D011995:Recombination, Genetic; D014611:Vaccination; D014614:Vaccines, Synthetic / Q000009:adverse effects
D020121:5' Untranslated Regions; D036022:Capsid Proteins; D011055:Poliovirus Vaccine, Oral; D014614:Vaccines, Synthetic