title: Molecular characterization and phylogenetic relationship of wild type 1 poliovirus strains circulating across Pakistan and Afghanistan bordering areas during 2010-2012.
abstract: Pakistan and Afghanistan share a long uncontrolled border with extensive population movement on both sides. Wild poliovirus transmission has never been interrupted in this block due to war against terrorism, poor public health infrastructure, misconceptions about polio vaccines and inadequate immunization activities. All these issues complicate the eradication operations and reinforce the complexity of wiping out poliomyelitis from this region. This study illustrates the origins and routes of cross-border wild poliovirus type 1 (WPV1) transmission during 2010-2012 between Pakistan and Afghanistan. Sequence analyses were conducted based on complete VP1 capsid protein sequences for WPV1 study strains to determine the origin of poliovirus genetic lineages and their evolutionary relationships. Phylogenetic tree was constructed from VP1 gene sequences applying Maximum Likelihood method using Kimura 2- parameter model in MEGA program v 5.0. A total of 72 (14.3%) out of 502 wild-type 1 polioviruses were found circulating in border areas of both countries during 2010-2012. Molecular phylogenetic analysis classified these strains in to two sub-genotypes with four clusters and 18 lineages. Genetic data confirmed that the most of WPV1 lineages (12; 66.6%) were transmitted from Pakistan to Afghanistan. However, the genetic diversity was significantly reduced during 2012 as most of the lineages were completely eliminated. In conclusion, Pakistan-Afghanistan block has emerged as a single poliovirus reservoir sharing the multiple poliovirus lineages due to uncontrolled movement of people across the borders between two countries. If it is neglected, it can jeopardize the extensive global efforts done so-far to eradicate the poliovirus infection. Our data will be helpful to devise the preventive strategies for effective control of wild poliovirus transmission in this region.
authors.affiliation: Department of Virology, National Institute of Health, Chak Shahzad, Islamabad, Pakistan.
authors.forename: Shahzad
authors.initials: S
authors.lastname: Shaukat
authors.affiliation: Department of Virology, National Institute of Health, Chak Shahzad, Islamabad, Pakistan.
authors.forename: Mehar
authors.initials: M
authors.lastname: Angez
authors.affiliation: Department of Virology, National Institute of Health, Chak Shahzad, Islamabad, Pakistan.
authors.forename: Muhammad Masroor
authors.initials: MM
authors.lastname: Alam
authors.affiliation: Department of Virology, National Institute of Health, Chak Shahzad, Islamabad, Pakistan.
authors.forename: Salmaan
authors.initials: S
authors.lastname: Sharif
authors.affiliation: Department of Virology, National Institute of Health, Chak Shahzad, Islamabad, Pakistan.
authors.forename: Adnan
authors.initials: A
authors.lastname: Khurshid
authors.affiliation: Department of Virology, National Institute of Health, Chak Shahzad, Islamabad, Pakistan.
authors.forename: Farzana
authors.initials: F
authors.lastname: Malik
authors.affiliation: Department of Virology, National Institute of Health, Chak Shahzad, Islamabad, Pakistan.
authors.forename: Lubna
authors.initials: L
authors.lastname: Rehman
authors.affiliation: Department of Virology, National Institute of Health, Chak Shahzad, Islamabad, Pakistan.
authors.forename: Syed Sohail Zahoor
authors.initials: SS
authors.lastname: Zaidi
mesh_terms: D000346:Afghanistan / Q000453:epidemiology; D005838:Genotype; D005843:Geography; D006801:Humans; D017720:Molecular Epidemiology; D010154:Pakistan / Q000453:epidemiology; D010802:Phylogeny; D011051:Poliomyelitis / Q000453:epidemiology / Q000635:transmission; D017955:Poliovirus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification