About National Surveillance
CDC collects data from all states on infections due to nationally notifiable enteric bacterial pathogens including Listeria monocytogenes, Salmonella spp, Shiga toxin-producing Escherichia coli (STEC), Shigella spp, and Vibrio spp (including V. cholerae). CDC also collects data from all states on cases of botulism, which is caused by toxins produced by Clostridium botulinum; botulism is also nationally notifiable. Information is gathered from both “laboratory-based” and “case-based” surveillance systems.
National Laboratory-based Surveillance
“Laboratory-based” surveillance relies on the collection of information about bacteria that have been identified by laboratory testing of ill persons. Bacteria are isolated and identified from patient specimens by clinical laboratories, and the isolates are then submitted to state public health laboratories for further characterization or reported to them. CDC conducts laboratory-based surveillance for infections caused by Salmonella, Shigella, and Shiga toxin-producing Escherichia coli (STEC) using reports from state and territorial public health laboratories.
National Case-based Surveillance
“Case-based” surveillance relies on the collection of reports of cases of illness. These case reports include information such as the symptoms of illness, when those symptoms started, demographic information about the ill person (age, sex, state of residence), and key risk factor information (e.g., travel, activities, foods consumed) for the specific infection. CDC conducts case-based surveillance for botulism, cholera and other Vibrio illnesses (including V. parahaemolyticus and V. vulnificus infections), Listeria infections, and typhoid and paratyphoid fever infections by collecting case report forms for each person who is diagnosed with a case of one of these illnesses. These data are reported to CDC by state and territorial public health departments.