The role of surveillance in polio eradication and identification of emerging viral encephalitis.
In 1988, when the World Health Assembly resolved to eradicate paralytic poliomyelitis, polio was endemic in 125 countries on 5 continents with an estimated 350,000 cases annually. By 2002, the number of countries was reduced to 7 and the number of cases by greater than 99%. Instrumental in this extraordinary progress is the timely detection and investigation of all cases of acute flaccid paralysis and the examination of stool samples in an accredited WHO Global Network laboratory. The Network consists of 124 National Poliovirus Laboratories, 15 Regional Reference Laboratories, and 7 Global Specialized Laboratories. Network Laboratories are held accountable to rigid performance standards for quality and timeliness in testing more than 60,000 stool samples annually. The Network is a hierarchical system in which polioviruses are isolated and identified in National Laboratories, differentiated as to wild or vaccine origin in Regional Reference Laboratories, and sequenced in Specialized Laboratories. Findings are promptly relayed to Regional and national program managers for immunization strategic planning, monitoring surveillance quality, and assessing eradication progress. Lessons from the Polio Laboratory Network demonstrate the value of a central coordinating body, an effective communication infrastructure, and full partnerships with peer epidemiology and medical sectors. Post-eradication polio surveillance will continue for many years. The Network legacy for other public health initiatives is access to an existing laboratory infrastructure and human resources with the proven ability to achieve technology transfer and quality laboratory performance even in resource-poor countries.
De Gourville
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Task Force for Child Survival and Development, Decatur, GA 30030, USA.
Dowdle
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D018792:Encephalitis, Viral / Q000453:epidemiology*; D005843:Geography; D006801:Humans; D007400:Interprofessional Relations; D011051:Poliomyelitis / Q000517:prevention & control*; D011634:Public Health; D014944:World Health Organization