i found out for anyone interested:
Reportable diseases are diseases considered to be of great public health importance. Local, state, and national agencies (for example, the Centers for Disease Control and Prevention) require that such diseases be reported when they are diagnosed by doctors or laboratories.
This permits surveillance (i.e., the collection of statistics on the frequency with which the disease occurs), which in turn allows these agencies to identify trends in disease occurrence, as well as disease outbreaks.
