According to a new U.S. Centers for Disease Control and Prevention (CDC) report, the incidence of most foodborne infections increased in 2018 compared to 2015-2017. 

Why the increase?
CDC attributes more illnesses to better detection, specifically the use of culture-independent diagnostic tests (CIDTs).

What did CDC learn?
The Foodborne Diseases Active Surveillance Network (FoodNet) conducts active, population-based surveillance for laboratory-diagnosed infections caused by Campylobacter, Cyclospora, Listeria, Salmonella, Shiga toxin–producing Escherichia coli (STEC), Shigella, Vibrio, and Yersinia in 10 sites covering 15 percent of the U.S. population (approximately 49 million persons in 2017).

• During 2018, FoodNet identified 25,606 infections, 5,893 hospitalizations, and 120 deaths.
• The incidence of infection was highest for Campylobacter (19.5 percent) and Salmonella (18.3 percent), followed by STEC (5.9 percent), Shigella (4.9 percent), Vibrio (1.1 percent), Yersinia (0.9 percent), Cyclospora (0.7 percent), and Listeria (0.3 percent).
• Compared with 2015–2017, the incidence significantly increased for Cyclospora (399 percent), Vibrio (109 percent), Yersinia (58 percent), STEC (26 percent), Campylobacter (12 percent), and Salmonella (9 percent).
• The number of bacterial infections diagnosed by CIDT (with or without reflex culture§) increased 65% in 2018 compared with the average annual number diagnosed during 2015–2017; the increase ranged from 29 percent for STEC to 311 percent for Vibrio.
• In 2018, the percentage of infections diagnosed by DNA-based syndrome panels was highest for Yersinia (68%) and Cyclospora (67%), followed by STEC (55%), Vibrio (53%), Shigella (48%), Campylobacter (43%), Salmonella (33%), and was lowest for Listeria (2%).

Additional findings

• Campylobacter has been the most commonly identified infection in FoodNet since 2013.
• The incidence of infections with Enteritidis, the most common Salmonella serotype, has not declined in over 10 years.
• Produce is a major source of foodborne illnesses (2). During 2018, romaine lettuce was linked to two multistate outbreaks of STEC O157 infections (8). The marked increase in reported Cyclospora infections was likely attributable to several factors including produce outbreaks and continued adoption of DNA-based syndrome panel tests.

What do these findings mean for public health?
As use of CIDTs increases, it is important to obtain and subtype isolates and interview ill persons to monitor prevention efforts and develop more targeted prevention and control measures to make food safer and decrease human illness.

What do these findings mean for industry?
More targeted prevention measures are needed on produce farms, food animal farms, and in meat and poultry processing establishments to make food safer and decrease human illness.
 

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