Abstract
Humans experienced various disease pandemics in the history of the world. Disease can spread over the world more rapidly and in larger scale than in any other time in the past as the world is getting smaller. The World Health Organization established its innovative event-based surveillance system in close collaboration with many partners at global scale for early detection and rapid response to the public health events (PHE) of international importance in 1997. It has been being strengthened to respond effectively to PHEs in harmony with the International Health Regulations which were revised in 2005.