This year’s FoodNet report summarizes 2017 preliminary surveillance data and describes trends since 2006 for infections caused by the following pathogens monitored by FoodNet: Campylobacter, Cryptosporidium, Cyclospora, Listeria, Salmonella, Shiga toxin-producing Escherichia coli (STEC), Shigella, Vibrio, Yersinia. The report also summarizes cases of hemolytic uremic syndrome (HUS) for 2016, the most recent year for which those data are available.

  • In 2017, FoodNet received reports of 24,484 illnesses, 5,677 hospitalizations, and 122 deaths in its surveillance area, which includes 15% of the U.S. population.
  • The incidence of infections per 100,000 people was highest for Campylobacter and Salmonella, which is similar to previous years.
  • The number of infections diagnosed by CIDT, a newer type of test, is increasing. The overall number of Campylobacter, Listeria, Salmonella, Shigella, Vibrio, and Yersinia infections diagnosed by CIDT increased 96% in 2017 compared with the 2014–2016 average.
  • CIDTs are revealing many infections – such as those caused by Cyclospora, Yersinia, Vibrio, and STEC non-O157 – that would not have been diagnosed before because of limited testing. CIDTs are fast and easy to use, and they detect some illnesses that would have otherwise been missed. However, CIDTs also challenge our ability to find outbreaks and monitor disease trends, because they do not provide certain information needed to characterize organisms that cause infections. For example, some information about the bacteria that cause infections, such as subtype and antimicrobial susceptibility, can be obtained only if a CIDT-positive specimen is cultured. FoodNet is gathering information to better understand the effect of CIDTs on surveillance.
  • The incidence of Salmonella infections overall did not change significantly, but there were significant changes among serotypes:
  • The incidence of infections caused by serotypes Typhimurium and Heidelberg has been decreasing since 2006–2008, with overall declines of more than 40% for both. Infections cause by serotypes Javiana, Thompson, and Infantis have all increased by more than 50% since 2006–2008.
  • Infections caused by STEC O157 have decreased in the past 10 years. The increasing use of CIDTs makes interpretation of trends in STEC infections difficult because CIDTs do not indicate which STEC serogroup caused the infection. The incidence of HUS among children younger than 5 years decreased during 2016 compared with 2006–2008. Because most cases of HUS are caused by STEC O157, the decline in HUS provides evidence that supports the finding of the decline in STEC O157 cases.