A novel magnetic beads-based method for polioviral concentration from environmental samples.

Environmental surveillance (EnvS)2 is an important tool for monitoring the presence of poliovirus in endemic and poliovirus free regions. Unlike acute flaccid paralysis (AFP)3 surveillance, EnvS can monitor large populations using small numbers of samples and detect the introduction of poliovirus even before the appearance of AFP cases. Early detection and timely response can prevent the onset of poliovirus associated AFP, as was demonstrated by silent poliovirus transmission in Israel in 2013. Although EnvS is currently recommended as supplementary to AFP surveillance, it is limited to laboratories with equipment for poliovirus concentration and to regions where samples can be easily transported under temperature controlled conditions to such facilities. However the highest risk of poliovirus re-emergence is in developing countries where such conditions do not exist. We developed and evaluated an affinity purification method using antibody or poliovirus receptor (CD155) presenting bacteriophage covered magnetic beads for poliovirus concentration. This method requires only simple, inexpensive and portable equipment. Though tested only on Sabin 1 spiked sewage samples it provided better recovery than our current polyethylene glycol (PEG)4/NaCl- based concentration method. On site use of this method might facilitate EnvS in currently inaccessible remote regions by significantly reducing the volume of sample that needs to be transported back to the laboratory under temperature-controlled conditions5.