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FoodNet Report: Pathogen Infection Rates Still ‘Well Above’ Government Targets

The U.S. Centers for Disease Control and Prevention released its latest report card on the trends in foodborne illnesses on Thursday, and, in general, not much has changed from previous years.

According to the Foodborne Diseases Active Surveillance Network (FoodNet), there were a total of 19,056 infections, 4,200 hospitalizations and 80 deaths reported in 2013.

FoodNet is a collaboration between CDC, 10 state health departments, the U.S. Department of Agriculture’s Food Safety and Inspection Service (FSIS) and the Food and Drug Administration that tracks incidents of Campylobacter, Listeria, Salmonella, Shigella, Shiga toxin-producing E. coli (STEC) O157, STEC non-O157, Vibrio, Yersinia, Cryptosporidium and Cyclospora.

As Food Safety News reported earlier this month, the number of laboratory-confirmed illnesses falls far below the actual number of people sickened by foodborne pathogens each year. CDC estimates that 48 million illnesses, 128,000 hospitalizations and 3,000 deaths are linked to foodborne illness annually.

One of the purposes of FoodNet is to help create a foundation for these estimates, as well as to identify areas of concern for subsequent policy and prevention efforts.

In 2013, the most common reports of infection were from Salmonella and Campylobacter. The incidence rate per 100,000 people was 15.19 for Salmonella and 13.82 for Campylobacter. They, along with STEC O157 and Vibrio, have rates “well above” their respective Healthy People 2020 targets, the report states.

In the short term, the rate of Salmonella dropped about 9 percent from the previous three years, but it was still at the same baseline levels of 2006-2008, continuing to remain above the government’s target of 11.4 per 100,000 people. FoodNet also suggested that the large Salmonella Enteritidis outbreak linked to eggs in 2010 might account for the incidence spike in 2010-2012.

One point drawing a lot of notice in the report is the increase in Vibrio infections, which are often linked to consuming raw shellfish. Although the pathogen accounted for only 1.3 percent of the reported infections in 2013, its incidence increased 32 percent from 2010-2012.

Robert Tauxe, deputy director of CDC’s Division of Foodborne, Waterborne and Environmental Diseases, noted that the number of Vibrio cases has increased 75 percent since 2006-2008 and 168 percent since 1996-1998.

“We’re at the highest level observed since our tracking began in 1996,” he said. “However, the rates of infection caused by Vibrio vulnificus, which is the most severe strain, have not increased particularly in recent years.”

The report also noted that, in the summers of 2012 and 2013, many of the Vibrio parahaemolyticus infections of a strain previously traced only to the Pacific Northwest were associated with consump­tion of oysters and other shellfish from several Atlantic coast harvest areas.

“E. coli infections continue to inch up and the progress that had been noted since 2006-2008 in past years has stalled,” Tauxe said.

The report also notes a “continued decrease” in incidents of HUS (hemolytic uremic syndrome), possibly due to unrecognized changes in surveillance, improvements in management of STEC O157, or a decrease in infections from the most virulent strains.

“Continued surveillance is needed to determine if this pattern holds,” the report concludes.

As for the other foodborne infections tracked, rates of infection compared to the 2010-2012 rates “haven’t changed much,” Tauxe said.

Relative rates of culture-confirmed infections with Campylobacter, STEC O157, Listeria, Salmonella, and Vibrio compared with 2006–2008 rates

Culture-independent diagnostic tests (CIDTs) are increasingly being used to diagnose bacterial enteric infections – mostly for Campylobacter and STEC. Any of these positive tests that were confirmed by culture were included in FoodNet’s statistic of 19,056 infections.

But FoodNet has also identified an additional 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.

FoodNet decided to start tracking these tests in 2013 to better understand their uptake, calling them “a trend that will chal­lenge the ability to identify cases, monitor trends, detect out­breaks, and characterize pathogens.”

There are currently no national guidelines for sending positive CIDTs for culture confirmation, but Caroline Smith DeWaal, food safety director for the Center for Science in the Public Interest, said that she wants CDC to develop a plan to address their increased use.

“Otherwise the trend of declining reporting of outbreaks may continue — not because fewer people are getting sick, but because state health departments and CDC cannot track the outbreaks,” she said.

During a press conference about the report, David Goldman, Assistant Administrator for the FSIS Office of Public Health Science, and Stephen Ostroff, FDA’s Acting Chief Scientist, laid out how their agencies hope to address the lack of progress in decreasing contamination.

For FSIS, Goldman referenced the proposed modernized poultry inspection rule, Salmonella performance standards for chicken parts and ground poultry (which are expected this fall), and education and outreach.

“While Salmonella-positive samples in young chickens have dropped over 75 percent since 2006, unfortunately this has not translated into domestic changes in Salmonellosis,” he said. “While we hope that all of these steps just outlined are headed in the right direction, this report reminds us that there is more work to be done.”

For FDA, implementing the Food Safety Modernization Act (FSMA) is at the top of the to-do list. Ostroff also cited progress made under the shell egg safety rule and work with partners to understand what circumstances are most associated with Vibrio illnesses.

“The findings, taken as a whole, reinforce the importance of moving forward with preventive measures that will help ensure food safety of every stage of production from the farm to the consumer,” Ostroff said.

Surveillance data from the annual reports FoodNet publishes help agencies know where to target prevention efforts. And, like consumer advocates calling for finalized policies and new regulatory approaches, this latest report states, “More can be done.”

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