The CDC maintains a periodically reviewed list of nationally notifiable infectious diseases. Ultimately, each state reports its set of reportable diseases to the CDC. However, each state has its own list of reportable diseases and reporting procedures. Usually cases are first reported to a local authority who then reports a case to a state authority. Once  cases have been reported to the appropriate state official(s) the data is then transmitted to the CDC  through the National Electronic Telecommunications System for Surveillance (NETSS). Once a disease is reported through NETSS it becomes part of the National Notifiable Diseases Surveillance System (NNDSS).