The National Salmonella Surveillance System and the National Shigella Surveillance System collect reports of isolates of Salmonella and Shigella from human sources from every state in the United States. This information is reported through the Public Health Laboratory Information System (PHLIS), an electronic reporting system, by the State Public Health Laboratory Directors and State and Territorial Epidemiologists to the Foodborne and Diarrheal Diseases Branch (FDDB) and the Biostatistics and Information Management Branch (BIMB) of the Division of Bacterial and Mycotic Diseases in the National Center for Infectious Diseases.
The number of isolates reported by geographical area (e.g. state) represents the state where laboratory confirmation was performed; in some instances the reporting state is not the same as the state of residence of the person from whom the isolate was obtained. For Salmonella serotype Typhi, only the first isolation in a year for each person is counted. For the Annual Tabulation Summaries, duplicate records are deleted.
The Salmonella Outbreak Detection Algorithm (SODA), developed by BIMB and FDDB, is a statistical algorithm designed to detect unusual clusters of isolates of Salmonella infection. SODA compares current Salmonella isolates reported through PHLIS by serotype to a 5-year historical baseline for that serotype and week to detect unusual increases from the baseline. Analyses can be conducted at state, regional, or national levels. Since 1996, SODA has been implemented at CDC and selected state health departments. If you would like more information on SODA, please call the PHLIS Helpdesk (404) 639-3365.
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