Salmonellosis Outbreaks by Food Vehicle, Serotype, Season, and Geographical Location, United States, 1998 to 2015

Abstract

ABSTRACT Salmonella is a major cause of foodborne illness in the United States. Although salmonellosis outbreaks are relatively common, food vehicles and other characteristics are not well understood. We obtained data for salmonellosis outbreaks from 1998 to 2015 that were submitted by public health jurisdictions to the Centers for Disease Control and Prevention's Foodborne Disease Outbreak Surveillance System. In total, 2,447 outbreaks (yearly average, 136) with a confirmed or suspected etiology of nontyphoidal Salmonella were identified. The outbreaks included 65,916 individual cases (mean, 27 cases per outbreak). Food vehicles were identified in 49% of the outbreaks. Frequently implicated foods included eggs (12.5%), chicken (12.4%), and pork (6.5%). Fifty-five (2.2%) outbreaks had fatalities; 87 (0.1%) individuals died. Of those outbreaks with a reported serotype, the most commonly identified were Enteritidis (29.1%), Typhimurium (12.6%), and Newport (7.6%). Serotypes with a statistically significant increase over time included Braenderup and I 4,[5],12:i:−. Some serotypes were commonly associated with outbreaks due to certain food vehicles; 81% of outbreaks due to eggs were associated with serotype Enteritidis. Food commodities that were most commonly associated with multistate outbreaks were nuts and seeds, sprouts, and fruits. Outbreaks occurred most frequently in summer. States with the highest number of salmonellosis outbreaks per 100,000 population were Alaska (0.137) and Minnesota (0.121); states with the lowest were Delaware (<0.001) and Wyoming (<0.001). The highest number of salmonellosis cases per 100,000 population were in Washington, DC (4.786) and Arkansas (3.857). Geographic variations in outbreaks may reflect differences in outbreak detection, investigation, reporting, or risk. In addition to collaboration, data-driven public health interventions are needed to decrease infection rates and to prevent complications related to salmonellosis. HIGHLIGHTS