Related Experiment Video
Updated: Apr 22, 2026
Particle Agglutination Method for Poliovirus Identification
Published on: April 20, 2011
Detection of multiple cocirculating wild poliovirus type 1 lineages through environmental surveillance: impact and
Muhammad Masroor Alam1, Shahzad Shaukat1, Salmaan Sharif1
1WHO Regional Reference Laboratory for Polio Eradication Initiative, Department of Virology, National Institute of Health, Chak Shahzad, Islamabad, Pakistan.
Background:
The environmental surveillance has proven to be a useful tool to identify poliovirus circulation in different countries and was started in Pakistan during July 2009 to support the acute flaccid paralysis (AFP) surveillance system.
Methods:
Sewage samples were collected from 27 environmental sampling (ENV) sites and processed for poliovirus isolation through 2-phase separation method. Poliovirus isolates were identified as Sabin-like or wild type through real-time polymerase chain reaction (PCR). Wild-type strains were subjected to VP1 gene sequencing and phylogenetic analysis performed using MEGA 5.0.
Results:
During 2011-2013, a total of 668 samples were collected from 4 provinces that resulted in 40% of samples positive for wild poliovirus type-1 (WPV-1). None of the samples were positive for WPV-3. The areas with high frequency of WPV-1 detection were Karachi-Gadap (69%), Peshawar (82%), and Rawalpindi (65%), whereas the samples from Quetta and Sukkur remained negative for WPV during 2013. Phylogenetic analysis revealed 3 major clusters with multiple poliovirus lineages circulating across different country areas as well as in bordering areas of Afghanistan.
Conclusions:
Environmental surveillance in Pakistan has been proven to be a powerful tool to detect WPV circulation in the absence of poliomyelitis cases in many communities. Our findings emphasize the need to continue and expand such surveillance activities to other high-risk areas in the country.
