The CDC published this week in MMWR that in August 2012, the Arkansas Department of Health (ADH) was notified of gastrointestinal illness outbreaks in two unnamed Arkansas state prisons. ADH investigated the outbreaks and conducted case-control studies to identify the source of the illnesses. The report described the results of these investigations, which identified 528 persons with onset of diarrhea during August 2–18, 2012.

Results from one prison investigation identified chicken salad as the most likely vehicle. At the second prison, person-to-person transmission and contamination of multiple foods likely contributed to illness.

Analysis of stool specimens from inmates identified eight serotypes and 15 pulsed-field gel electrophoresis (PFGE) patterns of Salmonella.

Isolates of Salmonella from eggs produced at the second prison matched two outbreak patterns. An additional 69 inmates were positive by culture but were not interviewed or did not report diarrhea, making the total case count 597.

Sanitarians identified problems with food preparation, hand washing, and food safety training.