title: Circulation of endemic type 2 vaccine-derived poliovirus in Egypt from 1983 to 1993.
abstract: From 1988 to 1993, 30 cases of poliomyelitis associated with poliovirus type 2 were found in seven governorates of Egypt. Because many of the cases were geographically and temporally clustered and because the case isolates differed antigenically from the vaccine strain, it was initially assumed that the cases signaled the continued circulation of wild type 2 poliovirus. However, comparison of sequences encoding the major capsid protein, VP1 (903 nucleotides), revealed that the isolates were related (93 to 97% nucleotide sequence identity) to the Sabin type 2 oral poliovirus vaccine (OPV) strain and unrelated (<82% nucleotide sequence identity) to the wild type 2 polioviruses previously indigenous to Egypt (last known isolate: 1979) or to any contemporary wild type 2 polioviruses found elsewhere. The rate and pattern of VP1 divergence among the circulating vaccine-derived poliovirus (cVDPV) isolates suggested that all lineages were derived from a single OPV infection that occurred around 1983 and that progeny from the initiating infection circulated for approximately a decade within Egypt along several independent chains of transmission. Complete genomic sequences of an early (1988) and a late (1993) cVDPV isolate revealed that their 5' untranslated region (5' UTR) and noncapsid- 3' UTR sequences were derived from other species C enteroviruses. Circulation of type 2 cVDPVs occurred at a time of low OPV coverage in the affected communities and ceased when OPV coverage rates increased. The potential for cVDPVs to circulate in populations with low immunity to poliovirus has important implications for current and future strategies to eradicate polio worldwide.
authors.affiliation: Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. CYang@cdc.gov
authors.forename: Chen-Fu
authors.initials: CF
authors.lastname: Yang
authors.forename: Tary
authors.initials: T
authors.lastname: Naguib
authors.forename: Su-Ju
authors.initials: SJ
authors.lastname: Yang
authors.forename: Eman
authors.initials: E
authors.lastname: Nasr
authors.forename: Jaume
authors.initials: J
authors.lastname: Jorba
authors.forename: Nahed
authors.initials: N
authors.lastname: Ahmed
authors.forename: Ray
authors.initials: R
authors.lastname: Campagnoli
authors.forename: Harrie
authors.initials: H
authors.lastname: van der Avoort
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shimizu
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Yoneyama
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Miyamura
authors.forename: Mark
authors.initials: M
authors.lastname: Pallansch
authors.forename: Olen
authors.initials: O
authors.lastname: Kew
mesh_terms: D000818:Animals; D036022:Capsid Proteins / Q000235:genetics; D004534:Egypt / Q000453:epidemiology; D019353:Endemic Diseases; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D011051:Poliomyelitis / Q000453:epidemiology* / Q000821:virology; D017955:Poliovirus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity; D011055:Poliovirus Vaccine, Oral; D017422:Sequence Analysis, DNA; D014611:Vaccination
chemical_list: D036022:Capsid Proteins; D011055:Poliovirus Vaccine, Oral; C442540:VP1 protein, Poliovirus