Norovirus, salmonella cause bulk of known US foodborne illness; meat, produce primary vehicles

The US. Centers for Disease Control reported today that in 2008, 1,034 foodborne disease outbreaks were reported, which resulted in 23,152 cases of illness, 1,276 hospitalizations, and 22 deaths. Among the 479 outbreaks with a laboratory-confirmed single etiologic agent reported, norovirus was the most common, accounting for 49% of outbreaks and 46% of illnesses. Salmonella was the second most common, accounting for 23% of outbreaks and 31% of illnesses. Among the 218 outbreaks attributed to a food vehicle with ingredients from only one of 17 defined food commodities, the top commodities to which outbreaks were attributed were poultry (15%), beef (14%), and finfish (14%), whereas the top commodities to which outbreak-related illnesses were attributed were fruits and nuts (24%), vine-stalk vegetables (23%), and beef (13%).

Since 1992, CDC has defined a foodborne disease outbreak as the occurrence of two or more similar illnesses resulting from ingestion of a common food. State, local, and territorial health department officials use a standard, Internet-based form to voluntarily submit reports of foodborne outbreaks to CDC. An online toolkit of clinical and laboratory information is available to support investigation and reporting of outbreaks.

The number (1,034) of outbreaks was 10% lower than the annual average reported (1,151) for 2003–2007, and the number of outbreak-related illnesses was 5% lower (23,152 versus 24,400).

Of the total number of outbreak-related foodborne illnesses, 1,276 (6%) resulted in hospitalization. Salmonella was the most common cause of outbreak-related hospitalizations, causing 62% of hospitalizations reported, followed by Shiga toxin–producing Escherichia coli (STEC) (17%) and norovirus (7%). Outbreaks caused by Clostridium botulinum resulted in the highest proportion of persons hospitalized (90%), followed by Listeria outbreaks (76%). Among the 22 deaths associated with foodborne disease outbreaks in 2008, 20 were attributed to bacterial etiologies (13 Salmonella, three Listeria monocytogenes, three STEC [two O157, one O111], one Staphylococcus), one to norovirus, and one to a mycotoxin.

Among the 868 outbreaks with a known single setting where food was consumed, 52% resulted from food consumed in a restaurant or deli, 15% in a private home, and the remainder in other locations.

Ref: Surveillance for foodborne disease outbreaks — United States, 2008. Morbidity and Mortality Weekly Report, September 9, 2011 / 60(35); 1197-1202.