28.06.2013

Gould et al (2013) MMWR, CDC

Foodborne diseases cause an estimated 48 million illnesses each year in the United States, including 9.4 million caused by known pathogens. Foodborne disease outbreak surveillance provides valuable insights into the agents and foods that cause illness and the settings in which transmission occurs. CDC maintains a surveillance program for collection and periodic reporting of data on the occurrence and causes of foodborne disease outbreaks in the United States. This surveillance system is the primary source of national data describing the numbers of illnesses, hospitalizations, and deaths; etiologic agents; implicated foods; contributing factors; and settings of food preparation and consumption associated with recognized foodborne disease outbreaks in the United States.

During 1998–2008, CDC received reports of 13,405 foodborne disease outbreaks, which resulted in 273,120 reported cases of illness, 9,109 hospitalizations, and 200 deaths. Of the 7,998 outbreaks with a known etiology, 3,633 (45%) were caused by viruses, 3,613 (45%) were caused by bacteria, 685 (5%) were caused by chemical and toxic agents, and 67 (1%) were caused by parasites.  Eight pathogens caused 89% of the 5,059 confirmed, single-etiology  outbreaks, including norovirus (39%), Salmonella (26%), Shiga toxin–producing E. coli (STEC) (6%), scombroid toxin/histamine (5%), Clostridium perfringens (5%), Staphylococcus enterotoxin (3%), ciguatoxin (3%), and Campylobacter jejuni (2%). Salmonella was the second most common etiology, causing 1,449 (18%) of the 7,998 outbreaks with a confirmed or suspected single etiology and 39,126 (19%) illnesses. Among the 1,291 outbreaks caused by Salmonella with a confirmed serotype, Enteritidis was the most common, causing 418 (32%) outbreaks, followed by Typhimurium (170 outbreaks [13%]), Heidelberg (102 outbreaks [8%]), and Newport (93 outbreaks [7%]). Outbreaks caused by Salmonella resulted in the largest number of reported hospitalizations (4,034 of 9,109 hospitalizations [44%]). Outbreaks caused by Salmonella  were associated most commonly with poultry (30%; CI = 25.7–34.2) and eggs (24%; CI = 20.5–28.3).

The percentage of outbreaks caused by Salmonella attributed to poultry varied over the four time intervals, ranging from 24% (CI = 15.5–32.7) to 33% (CI = 24.2–42.0). The percentage of outbreaks caused by Salmonella attributed to eggs declined significantly from 33% (CI = 24.0–42.9) during 1998–1999 to 15% (CI = 8.0–22.0) during 2006–2008. Outbreaks caused by Salmonella serotype Enteritidis were attributed commonly to eggs (64%; CI = 56.4–71.7) and poultry (18%; CI = 12.1–24.9). Poultry was also the commodity implicated most commonly in outbreaks caused by serotype Typhimurium (36%; CI = 21.9–49), but poultry was not implicated significantly more often than pork or dairy.
Among the 7,724 (58%) outbreaks with an implicated food or contaminated ingredient reported, 3,264 (42%) could be assigned to one predefined commodity categories. The commodities implicated most commonly were poultry (18.9%; 95% confidence interval [CI] = 17.4–20.3) and fish (18.6%; CI = 17.2–20).