[Surveillance strategy for viral zoonotic diseases]

Public health surveillance is the ongoing systematic collection, analysis, interpretation, and dissemination of health data. In fact, public health surveillance has been defined quite succinctly as "information for action". Recently, many outbreaks of virus zoonoses are reported in the world, which include West Nile virus disease, avian influenza and severe acute respiratory syndrome (SARS). Public health surveillance is a powerful tool for prevention. However establishing of public health surveillance systems are very difficult for random sampling, sample size and cost. The surveillance of Japanese encephalitis virus activity has been effectively conducted by using seroprevalence of pigs for more than 20 years in Japan. Polio acute flaccid paralysis (AFP) surveillance has been also effectively conducted, although polio cases are decreasing in the world. It is important to understand the character of disease for constructing effective public surveillance systems.