TYLER, Texas (KLTV) - When a test comes back positive for a reportable illness in East Texas, epidemiologists at the Northeast Texas Public Health District get to work - tracing contacts, reviewing exposures, and searching for a common source before a single case becomes an outbreak.

How cases are trackedNET Health monitors diseases in East Texas year-round, working to prevent outbreaks of nearly 100 reportable illnesses.

The process begins at a doctor's office.