Cuneatus

Alexander Langmuir, expert in public health surveillance and intelligence     Alexander Langmuir, the man behind epidemiologic intelligence, gave a crystal clear definition of surveillance as it applies to public health. He defined it as the continued watchfulness, systematic collection, consolidation and interpretation of public health data, and dissemination of this information to people who are in a position to take action. Surveillance is not static, but dynamic. Surveillance system must be flexible. It should adapt itself to the changing epidemiology of the problem under surveillance. There was an era when measles in India was under event-based surveillance. But it is now realized that in order to achieve elimination of measles, we should move on to case-based surveillance where every case of measles has to be investigated and control measures promptly instituted. Though not in the literal sense, surveillance can afford to be less rigorous when the disease has a low killi