(HealthDay News) – Compared with earlier outbreaks, more recent food-associated listeriosis outbreaks in the United States have been shorter and affected fewer people, according to research published online Dec. 12 in Emerging Infectious Diseases.
Emily J. Cartwright, MD, of the U.S. Centers for Disease Control and Prevention in Atlanta, and colleagues provide a summary of listeriosis outbreaks reported to the Foodborne Disease Outbreak Surveillance System of the CDC during 1998–2008, including data from PulseNet, a molecular subtyping network, and the Listeria Initiative (enhanced surveillance for investigation of outbreaks).
During the study period, the researchers identified reports of 24 confirmed listeriosis cases, resulting in 359 illnesses, 215 hospitalizations, and 38 deaths. Outbreaks occurring earlier in the study period (13 outbreaks) tended to be larger and longer than those occurring later (median 11 vs. five cases; 122 vs. 36 days). Earlier cases were associated with ready-to-eat meats (five with deli meats and three with frankfurters). In contrast, outbreaks occurring later in the study period were associated with novel vehicles, including sprouts, taco/nacho salad, and tuna salad. Serotype 4b was found in the largest number of outbreaks and in seven cases linked with outbreaks.
“Listeriosis outbreak investigations are crucial to prevent additional illness, hospitalization, and death,” the authors write. “The changes we observed in characteristics of listeriosis outbreaks during 1998–2008 illustrate the contributions of PulseNet and the Listeria Initiative for outbreak detection and investigation and subsequent effects of industry and regulatory efforts to prevent similar contamination from reoccurring.”