Wild poliovirus type 1 and type 3 importations–15 countries, Africa, 2008-2009

The Global Polio Eradication Initiative began in 1988; by 2006, indigenous transmission of wild poliovirus (WPV) type 2 infection had been interrupted globally, and indigenous transmission of type 1 and 3 (WPV1 and WPV3) infection had been interrupted in all but four countries worldwide (Afghanistan, India, Nigeria, and Pakistan). Despite this success in controlling indigenous transmission, during 2002-2006, 20 previously polio-free countries in Africa and Asia had importations of WPV1 originating from Nigeria, and three polio-free countries in Africa had WPV1 importations originating from India. By the end of 2007, control efforts in all countries except Angola, Chad, Democratic Republic of the Congo (DRC), Niger, and Sudan had stopped transmission of WPV1 caused by these importations. However, during 2008-2009, multiple importations of WPV from countries with ongoing transmission resumed in Africa. This report describes 32 WPV importations into 15 African countries, resulting in 96 polio cases during January 2008-March 2009 and persistent WPV transmission in five previously polio-free African countries. As with the 2002-2006 resurgence, all of the importations originated from Nigeria or India, but more rapid WPV identification and response resulted in substantially fewer polio cases than reported during 2002-2006. Sensitive surveillance and continued rapid response supplemental immunization activities (SIAs) are key to limiting further WPV spread, interrupting the outbreaks, and allowing the polio prevention focus in Africa to return to eradicating polio in countries with persistent WPV transmission.