Progress toward poliomyelitis eradication--Afghanistan and Pakistan, January 2003-May 2004.

Since the 1988 World Health Assembly resolution to eradicate poliomyelitis, the number of countries where polio is endemic decreased from approximately 125 to six by the end of 2003. In 2003, poliovirus importations were reported in 10 countries, including eight in West and Central Africa, one in Southern Africa (Botswana), and one in the Middle East (Lebanon). Two countries where poliovirus remains endemic are Afghanistan and Pakistan, which are analyzed together because of their geographic proximity, frequent cross-border population movements, and genetically similar wild poliovirus (WPV) lineages. This report describes intensified polio eradication activities in Afghanistan and Pakistan during January 2003-May 2004, summarizes progress made toward eradication, and highlights the remaining challenges to interrupting poliovirus transmission.