Establishing acute flaccid paralysis surveillance under difficult circumstances: lessons learned in Cambodia

The implementation of the World Health Organization's recommended strategies for polio eradication, particularly acute flaccid paralysis (AFP) surveillance, can be limited by difficult circumstances beyond the control of immunization personnel. In Cambodia, however, obstacles to establishing AFP surveillance were rapidly overcome using a strategy that improved reporting through active surveillance in a geographically limited area before gradually expanding to include the whole country. The success of the strategy was ensured by the timely provision of the resources that were needed to establish, expand, and monitor surveillance activities.