1. TB is one of the most important notifiable diseases worldwide. Notifications are the most important source of data for following the epidemiology of TB and for initiation of contact tracing.

2-4. Surveillance includes monitoring death certificates, or contacts with health services used by patients with TB: chest clinics, outpatient clinics, hospital admission, other health facilities.

All these sources have certain limitations in terms of accuracy and completeness. In particular, developing countries tend to have more basic health services and also poorer information. Data on TB, especially morbidity, are likely to be underestimates.