Disease surveillance is the ongoing tracking, monitoring and reporting of disease outbreaks to control the spread of disease. Synonyms for disease surveillance include public health surveillance, epidemiological surveillance, health monitoring, disease monitoring, outbreak detection and response, and disease intelligence. These terms imply a systematic and continuous effort to collect and analyze data on the occurrence, distribution, and trends of disease, in order to prevent or mitigate their impacts. Disease surveillance is essential for early detection, intervention, and control of infectious diseases, and can help inform public health policies and strategies to protect communities from the spread of disease.