Listeriosis outbreaks and associated food vehicles, United States, 1998-2008

Abstract

Listeria monocytogenes, a bacterial foodborne pathogen, can cause meningitis, bacteremia, and complications during pregnancy. This report summarizes listeriosis outbreaks reported to the Foodborne Disease Outbreak Surveillance System of the Centers for Disease Control and Prevention during 1998-2008. The study period includes the advent of PulseNet (a national molecular subtyping network for outbreak detection) in 1998 and the Listeria Initiative (enhanced surveillance for outbreak investigation) in 2004. Twenty-four confirmed listeriosis outbreaks were reported during 1998-2008, resulting in 359 illnesses, 215 hospitalizations, and 38 deaths. Outbreaks earlier in the study period were generally larger and longer. Serotype 4b caused the largest number of outbreaks and outbreak-associated cases. Ready-to-eat meats caused more early outbreaks, and novel vehicles (i.e., sprouts, taco/nacho salad) were associated with outbreaks later in the study period. These changes may reflect the effect of PulseNet and the Listeria Initiative and regulatory initiatives designed to prevent contamination in ready-to-eat meat and poultry products.

Figure 1

Reported listeriosis outbreaks by single-state or multistate status and total number of outbreak-associated cases, Foodborne Disease Outbreak Surveillance System, United States, 1998–2008 (n = 24 outbreaks). White bar sections indicate single state-and multistate outbreaks, gray bar sections indicate multistate outbreaks, and black line indicates total ill.

Figure 2

Distribution of single-state single and multistate outbreaks of listeriosis, 1998–2008, Foodborne Disease Outbreak Surveillance System, United States, 1998–2008 (n = 24 outbreaks). Dark gray indicates single-state and multistate outbreaks, and light gray indicates multistate outbreaks. Values indicate total outbreaks in each state. The grand total of outbreaks indicated in each state is greater than 24 because of multistate outbreaks.

Figure 3

Incidence of all cases (per million) and outbreaks of listeriosis, 1978–2008, United States. White bar sections indicate single-state outbreaks, gray bar sections indicate multisite outbreaks, and black line indicates incidence per million. Data were obtained from the Foodborne Diseases ActiveSurveillance Network (FoodNet) and the Foodborne Disease Outbreak Surveillance System. Data are as of June 2010.