Angola is experiencing one of the most severe polio epidemics that international organizations have seen worldwide in a decade. By May 11, 1999, the World Health Organization (WHO) had received official reports of 818 cases of polio (up from 200 in early April), almost all in young children. Resumption of civil war has facilitated the epidemic. Thousands of unimmunized children from rural families that migrated to Lusanda are living in severely crowded conditions with inadequate sanitation. The Angolan health ministry has immunized more than 635,000 children in Lusanda and a further 300,000 in Benguela. A nationwide campaign is planned to reach more than 3 million children under 5 years of age. WHO hopes that truces will be negotiated to enable immunization teams to reach children in the most disrupted parts of the country.