According to the CDC, the annual incidence of laboratory-confirmed listeriosis in the United States is about 0.24 cases per 100,000 population, based on active surveillance in 10 FoodNet sites. The U.S. Healthy People 2020 target for listeriosis is 0.2 cases per 100,000. Approximately 800 laboratory-confirmed cases are reported annually to CDC’s National Notifiable Disease Surveillance System. However, many cases are not detected or reported, and CDC’s 2011 Estimates of Foodborne Illness, which includes estimates of cases not diagnosed or reported, indicates that approximately 1,600 cases occur annually in the United States. CDC estimates that listeriosis is the third leading cause of death from foodborne illness with about 260 deaths per year. Nearly everyone with listeriosis is hospitalized. The case-fatality rate is about 20%. Nearly 25% of pregnancy-associated cases result in fetal loss or death of the newborn.
Presently the FDA, FSIS and CDC note on their respective websites to the investigation of Listeria outbreaks. It is unclear if the ones noted by the FDA and FSIS are the same investigation into the same yet unnamed product and if the CDC list includes those investigations as well. The FDA and FSIS generally oversees different food products. FSIS oversees, Beef, ,Chicken, Pork and Catfish. FDA generally oversees all other food products.
What makes the investigation of a Listeria outbreak a challenge is that the length of time between ingestion of the contaminated food product van vary. The incubation period for Listeria monocytogenes, the bacteria that causes listeriosis, can vary widely. It typically ranges from a few days to up to 30 days or more after consuming contaminated food. However, in some cases, it can extend even longer, up to 70 days, before symptoms appear.
