Variability among states in investigating foodborne disease outbreaks

Over 1,100 foodborne disease outbreaks cause over 23,000 illnesses in the United States annually, but the rates of outbreaks reported and successful investigation vary dramatically among states. We used data from the Centers for Disease Control and Prevention's outbreak reporting database, Association of Public Health Laboratories' PulseNet laboratory subtyping network survey and Salmonella laboratory survey, national public health surveillance data, and national surveys to examine potential causes of this variability. The mean rate of reporting of Salmonella outbreaks was higher in states requiring submission of all isolates to the state public health laboratory, compared to those that do not (5.9 vs. 4.1 per 10 million population, p=0.0062). Rates of overall outbreak reporting or successful identification of an etiology or food vehicle did not correlate at the state level with population, rates of sporadic disease reporting, health department organizational structure, or self-reported laboratory or epidemiologic capacity. Foodborne disease outbreak surveillance systems are complex, and improving them will require a multi-faceted approach to identifying and overcoming barriers.