Introduction: In some countries, wild polioviruses have been isolated from environment without being recovered from clinical cases. Therefore, to confirm polio eradication, WHO has recommended environmental surveillance using sewage specimens and surface water. Due to wild Poliovirus circulation in Afghanistan and Pakistan and the probability of wild virus entrance to Iran, and also to assure wild poliovirus eradication, Tehran was chosen as the target area.

Methods: In this study, 63 sewage samples were obtained from 6 main sewage disposals in Tehran by grab sampling and direct, pellet, two-phase method in sensitive cell lines. The isolated viruses were serotyped by microneutralization method and differentiated intratypically by ELISA and probe hybridization techniques.

Results: From all specimens, only 14 (22.22%) were identified as poliovirus, none of which were wild type. From these polioviruses, 6(9.52%), 13(20.63%) and 14(22.22%) were isolated from direct, pellet and two-phase concentrated specimens, respectively. The most frequent viruses were Polio1 and Polio2 (14.28%) and Polio 3(71.43%). Conclusion: Results have revealed the efficacy of immunization coverage and surveillance programs in Iran.

 Hakim Research Journal 2007 10(1):43 -49.