Trends in Foodborne Illness in the United States,
Documenting trends in foodborne illness—which illnesses are decreasing and which are increasing—is essential to the overall goal of reducing foodborne illness. FoodNet has been tracking trends in the most common infections transmitted through food since 1996.
Each year, FoodNet reports on the changes in the number of people in the United States sickened with foodborne infections that have been confirmed by laboratory tests. This annual report card also lets CDC, its partners, and policy makers know how much progress has made in reaching national goals for reducing foodborne illness.
FoodNet collects and monitors information on laboratory-confirmed illnesses for about 48 million people—or, about 15 percent of the American population. FoodNet data provide the best measure of trends in foodborne disease in the United States. The 2013 data showed that foodborne infections continue to be an important public health problem in the United States and highlight the need to move forward with preventive measures.
- FoodNet identified 19,056 cases of culture-confirmed bacterial and laboratory-confirmed parasitic infection, 4,200 hospitalizations, and 80 deaths among 48 million residents of 10 states (15% of the US population).
- The most frequent infection was caused by Salmonella accounting for 38% of reported infections, and the second by Campylobacter (35%). Vibrio accounted for 1.3% of reported infections.
- Although the incidence of Salmonella infection (15.19 per 100,000 population) was lower in 2013 than in 2010–2012, it remains similar to 2006–2008, well above the national Healthy People objective (11.4 cases per 100,000 population)
- Among serotyped Salmonella isolates, the top serotypes were Enteritidis, 1,237 (19%); Typhimurium, 917 (14%); and Newport, 674 (10%)
- The incidence of serotype Enteritidis infection was lower in 2013 than in 2010–2012, but not than in 2006–2008. This may be partly explained by the large Enteritidis outbreak linked to eggs in 2010.
- The incidence of Vibrio infections (0.51 per 100,000 population) was higher in 2013 than 2010–2012 and 2006–2008.
- Among speciated Vibrio isolates, the majority were Vibrio parahaemolyticus (62%)
- During the summers of 2012 and 2013, infections with a particular strain of V. parahaemolyticus serotype O4:K12 were associated with consuming shellfish from several Atlantic coast harvest areas. Before 2012, infections of serotype O4:K12 had not been associated with shellfish outside the Pacific Northwest region of the United States.
- Diagnostic practices are changing. New culture independent diagnostic tests (CIDTs) are increasingly used by clinical laboratories to diagnose bacterial enteric infections. These tests do not by themselves isolate a living germ in a laboratory culture that can be further studied.
- FoodNet has begun tracking the use of these new diagnostic tests, so that we can better understand their uptake. To date these tests are mostly being used for Campylobacter and STEC.
- In addition to culture-confirmed bacterial infections reported in FoodNet, there were 1,487 reports of positive CIDTs that were not confirmed by culture, either because the specimen was not cultured or because a culture did not yield the pathogen. These were not counted in the rates that are reported.
Comparison of the 2013 FoodNet data with data from 2006 through 2008 shows:
- Incidence of infection with Campylobacter and Vibrio were both higher in 2013. Rates of the other pathogens did not change significantly
- The incidence of Campylobacter infections, often linked to contaminated chicken, have risen 13 percent since 2006–2008
- The incidence of Vibrio infection, often linked to eating raw shellfish, was 75 percent higher
- The overall incidence of infection with six key foodborne pathogens (Campylobacter, Listeria, Salmonella,STEC O157, Vibrio, and Yersinia) did not change
- In 2012, the incidence of HUS was 36% lower among children aged <5 years compared with rates from 2006–2008 (complete HUS case detection lags behind the rest of FoodNet surveillance)
Recent Efforts and Next Steps
Most foodborne illnesses can be prevented. Some progress has been made in decreasing contamination of some foods and reducing illness caused by some pathogens. Recent efforts to reduce contamination of food and prevent these illnesses include:
- Establishment in 2011 of performance standards for Campylobacter contamination of whole broiler chickens in processing plants.
- Approval of more stringent time and temperature controls for oysters after harvest to prevent Vibrio vulnificus infections.
- The Food Safety Modernization Act of 2011: It gives FDA additional authority to regulate food facilities, establish standards for safe produce, recall contaminated foods, oversee imported foods, and which requires improvements in surveillance and response to outbreaks. It calls on CDC to strengthen surveillance and outbreak response.
More can be done. Determining where to target prevention efforts that will reduce foodborne infections requires continued collection of information to understand sources of infection, implementation of measures known to reduce food contamination, and development of new measures.