| environmental surveillance system to track wild poliovirus transmission. | eradication of poliomyelitis from large metropolis cities in india has been difficult due to high population density and the presence of large urban slums. three paralytic poliomyelitis cases were reported in mumbai, india, in 1999 and 2000 in spite of high immunization coverage and good-quality supplementary immunization activities. we therefore established a systematic environmental surveillance study by weekly screening of sewage samples from three high-risk slum areas to detect the silent tr ... | 2003 | 12732567 |