Infectious Diseases 2018

Infectious Diseases 2018

USA: Trends of foodborne illness outbreaks from 2006 to 2017

24 March, 2018

The CDC is examining trends of foodborne illness outbreaks for 2017 and describes changes in incidence since 2006 in its Morbidity and Mortality Weekly Report (MMWR) for March 23, 2018. Foodborne illness is a substantial health burden in the Untied States. In 2017, there were 24,484 infections, 5,677 hospitalizations, and 122 deaths attributed to food borne illness. Despite ongoing food safety measures in the United States, foodborne illness continues to be a substantial health burden. Compared with 2014–2016, the 2017 incidence of infections with Campylobacter, Listeria, non-O157 Shiga toxin–producing Escherichia coli (STEC), Yersinia, Vibrio, and Cyclospora increased. The increased incidences of pathogens for which testing was previously limited might have resulted from the increased use and sensitivity of culture-independent diagnostic tests (CIDTs), which can improve incidence estimates. Compared with 2006–2008, the 2017 incidence of infections with Salmonella serotypes Typhimurium and Heidelberg decreased, and the incidence of serotypes Javiana, Infantis, and Thompson increased. New regulatory requirements that include enhanced testing of poultry products for Salmonella† might have contributed to the decreases. 
The incidence of infection per 100,000 population was highest for Campylobacter (19.2) and Salmonella (16.0). Compared with incidence during 2014–2016, the 2017 incidence was significantly higher for Campylobacter (10% increase).
Among 6,373 (89%) fully serotyped Salmonella isolates, the five most common were Enteritidis (incidence = 2.6 per 100,000), Typhimurium (1.4), Newport (1.3), Javiana (1.1), and the monophasic variant of Typhimurium, I 4,[5],12:i:- (0.9). Among the 13 most common serotypes, the incidence for Heidelberg in 2017 was 65% lower than during 2006–2008 and 38% lower than during 2014–2016. It was also significantly lower for Typhimurium for both periods (42% and 14%, respectively).
Infections caused by serotypes Typhimurium (including I 4,[5],12:i:-) and Heidelberg have decreased considerably over the past 10 years. These declines mirror decreases in broiler chicken samples that yielded Salmonella and, specifically, serotype Heidelberg. These declines might be partly because of industry measures to vaccinate poultry flocks against these serotypes as well as implementation of measures by USDA-FSIS to decrease Salmonella in poultry and beef products.
Despite these decreases, the overall incidence of Salmonella has not substantially declined since 2014–2016, partly because infections with some serotypes have increased. In particular, infections caused by serotypes Javiana, Thompson, and Infantis each increased approximately 50% compared with 2006–2008. Like most serotypes, these have been linked to both food and other exposures, including animal contact. USDA-FSIS also noted an increase of >50% in the percentage of broiler chicken samples that yielded Infantis from 2006 to 2017.