Tag Archives: Foodnet

FoodNet Canada, 2019

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The Public Health Agency of Canada’s (PHAC) FoodNet Canada surveillance system (no, not that one, right, that’s the Canadian television network that wanted to sue me over video associated with 2004’s cooking show paper) is pleased to present this tables and figures report which provides the annual results of our surveillance activities conducted in 2019. The report is based on findings from its sentinel sites in British Columbia, Alberta, and Ontario. It also provides preliminary findings from Quebec, representing a partial year due to their implementation part way through the year in July 2019. The report focuses on trends in enteric pathogen disease rates, as well as trends in the prevalence of these pathogens found on potential disease sources: retail meats, manure from food producing animals and water. It is our hope that this report will be used to inform and shape discussions on food safety issues regarding enteric diseases and their sources.

Key findings:

  • In 2019, Campylobacter and Salmonella remained the most common causes of human enteric illness in the FoodNet Canada sentinel sites.
  • Travel continues to be an important factor in the burden of enteric disease. In 2019, approximately 30% of all cases of enteric disease were associated with travel outside of Canada.
  • Exposure to retail meat products remains a potential source of infection for human enteric illness. However, decreases in the prevalence of certain pathogen-food combinations were observed in 2019. For example, Salmonella on frozen breaded chicken products significantly decreased in 2019 compared to 2018 and is likely associated with interventions implemented at the industry level in 2019.
  • Other exposures, such as the farm environment and water, are also possible sources of infection for human enteric illness, with differences noted between the sites. For example, Salmonella is commonly found in broiler chicken manure, however, the prevalence significantly increased in BC whereas it significantly decreased in the AB site in 2019, resulting in an overall significant decrease in the combined sites.
  • The majority of clinical cases of shigatoxigenic Escherichia coli (STEC) were domestically acquired in 2019, with a significant increase in both travel and endemic incidence rates, which is primarily driven by the AB sentinel site who test all STEC-confirmed stool samples for non-O157 serogroups.
  • In 2019, surface water sampling was initiated for the first time in the ON site for STEC testing. The prevalence of STEC in the ON site (27%) was similar to the combined BC and AB irrigation water prevalence in 2019 (28%). · Continued monitoring of human illness and the potential exposures is important to ensure the continued health and safety of Canadians. The collection and integration of information across all of FoodNet Canada surveillance components (human, retail, on-farm, and water) in an enhanced and standardized way allows for the analysis of subtype distributions among human cases and potential exposure sources over time. This report will be followed by a comprehensive annual report, which will include more extensive analyses of temporal trends and subtyping information for an integrated perspective on enteric disease from exposure to illness.

Rates of FBI going nowhere

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Is unconditional love a real thing? Is it possible to maximize an individual’s goals and relationships at the same time? Is microbial foodborne illness still a thing?

Unconditional is a subjective word that means different things to different people.

Rather than going for the safe middle in conflict resolution, I have a therapist who says, go for the jugular: have a great relationship and go after great goals (note: it helps if you tell your partner what you want in terms of the relationship and goals).

Microbial foodborne illness rates in the U.S. have been stagnant for 15 years. It’s a thing, but it’s not clear who cares.

The Washington Post stated back in the day, “Between 1998 and 2004, illnesses reported by CDC that were caused by E. Coli, listeria, campylobacter and a few other bacteria decreased by 25 to 30 percent, perhaps because of improvements in the handling of meat and eggs. Since about 2004, however, the rate of these illnesses has basically remained steady.”

There’s lots of new media toys out there, but it’s the high-tech version of signs that say, “Employees Must Wash Hands.” Reposting press releases – especially in the absence of critical analysis — is a waste of bandwidth and resources. And there is no evidence it results in fewer sick people.

Last week, the U.S. Centers for Disease Control reiterated the incidence of most infections transmitted commonly through food has not declined for many years.

Incidence of infections caused by Listeria, Salmonella, and Shigella remained unchanged, and those caused by all other pathogens reported to FoodNet increased during 2019. Infections caused by Salmonella serotype Enteritidis, did not decline; however, serotype Typhimurium infections continued to decline.

New strategies that target particular serotypes and more widespread implementation of known prevention measures are needed to reduce Salmonella illnesses. Reductions in Salmonella serotype Typhimurium suggest that targeted interventions (e.g., vaccinating chickens and other food animals) might decrease human infections. Isolates are needed to subtype bacteria so that sources of illnesses can be determined.

I’ve been harping about the need for new messages and new media for 15 years – even did a road trip in 2009 with a number of talks stressing this point – with apparently little effect.

So maybe I’ll focus on relationships and being the best partner, father and person I can be.

Peace and love.

Preliminary incidence and trends of infections with pathogens transmitted commonly through food—foodborne diseases active surveillance network, 10 US sites, 2016-2019, 01 May 2020

Morbidity and Mortality Weekly Report pp.509-514

Danielle M. Tack, DVM1; Logan Ray, MPH1; Patricia M. Griffin, MD1; Paul R. Cieslak, MD2; John Dunn, DVM3; Tamara Rissman, MPH4; Rachel Jervis, MPH5; Sarah Lathrop, PhD6; Alison Muse, MPH7; Monique Duwell, MD8; Kirk Smith, DVM9; Melissa Tobin-D’Angelo, MD10; Duc J. Vugia, MD11; Joanna Zablotsky Kufel, PhD12; Beverly J. Wolpert, PhD13; Robert Tauxe, MD1; Daniel C. Payne, PhD1

https://www.cdc.gov/mmw/volumes/69/wr/mm6917a1.htm?s_cid=mm6917a1_w&deliveryName=USCDC_921-DM26943

Listeria happens in lotsa folks, and not pretty

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Listeria monocytogenes is a foodborne pathogen that disproportionally affects pregnant females, older adults, and immunocompromised individuals. Using U.S. Foodborne Diseases Active Surveillance Network (FoodNet) surveillance data, we examined listeriosis incidence rates and rate ratios (RRs) by age, sex, race/ethnicity, and pregnancy status across three periods from 2008 to 2016, as recent incidence trends in U.S. subgroups had not been evaluated. The invasive listeriosis annual incidence rate per 100,000 for 2008–2016 was 0.28 cases among the general population (excluding pregnant females), and 3.73 cases among pregnant females.

For adults ≥70 years, the annual incidence rate per 100,000 was 1.33 cases. No significant change in estimated listeriosis incidence was found over the 2008–2016 period, except for a small, but significantly lower pregnancy-associated rate in 2011–2013 when compared with 2008–2010. Among the nonpregnancy-associated cases, RRs increased with age from 0.43 (95% confidence interval: 0.25–0.73) for 0- to 14-year olds to 44.9 (33.5–60.0) for ≥85-year olds, compared with 15- to 44-year olds. Males had an incidence of 1.28 (1.12–1.45) times that of females. Compared with non-Hispanic whites, the incidence was 1.57 (1.18–1.20) times higher among non-Hispanic Asians, 1.49 (1.22–1.83) among non-Hispanic blacks, and 1.73 (1.15–2.62) among Hispanics. Among females of childbearing age, non-Hispanic Asian females had 2.72 (1.51–4.89) and Hispanic females 3.13 (2.12–4.89) times higher incidence than non-Hispanic whites. We observed a higher percentage of deaths among older patient groups compared with 15- to 44-year olds.

This study is the first characterizing higher RRs for listeriosis in the United States among non-Hispanic blacks and Asians compared with non-Hispanic whites. This information for public health risk managers may spur further research to understand if differences in listeriosis rates relate to differences in consumption patterns of foods with higher contamination levels, food handling practices, comorbidities, immunodeficiencies, health care access, or other factors.

Differences among incidence rates of invasive Listeriosis in the U.S. FoodNet population by age, sex, race/ethnicity, and pregnancy status, 2008–2016

Pohl, A. M., Pouillot, R., Bazaco, M. C., Wolpert, B. J., Healy, J. M., Bruce, B. B., . . . Doren, J. M. (2019).

doi:10.1089/fpd.2018.2548

https://www.liebertpub.com/doi/full/10.1089/fpd.2018.2548

Kids, kids, the FoodNet data is back

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The incidence of infections transmitted commonly through food has remained largely unchanged for many years. Culture-independent diagnostic tests (CIDTs) are increasingly used by clinical laboratories to detect enteric infections. CIDTs benefit public health surveillance by identifying illnesses caused by pathogens not captured routinely by previous laboratory methods.

Decreases in incidence of infection of Shiga toxin–producing Escherichia coli (STEC) O157 and Salmonella serotypes Typhimurium and Heidelberg have been observed over the past 10 years. These declines parallel findings of decreased Salmonella contamination of poultry meat and decreased STEC O157 contamination of ground beef.

As use of CIDTs continues to increase, higher, more accurate incidence rates might be observed. However, without isolates, public health laboratories are unable to subtype pathogens, determine antimicrobial susceptibility, and detect outbreaks. Further prevention measures are needed to decrease the incidence of infection by pathogens transmitted commonly through food.

Despite ongoing food safety measures in the United States, foodborne illness continues to be a substantial health burden. The 10 U.S. sites of the Foodborne Diseases Active Surveillance Network (FoodNet)* monitor cases of laboratory-diagnosed infections caused by nine pathogens transmitted commonly through food. This report summarizes preliminary 2017 data and describes changes in incidence since 2006.

In 2017, FoodNet reported 24,484 infections, 5,677 hospitalizations, and 122 deaths. 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 (1). 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 STEC O157 infections during 2017 also decreased compared with 2006–2008, which parallels reductions in isolations from ground beef.§ The declines in two Salmonella serotypes and STEC O157 infections provide supportive evidence that targeted control measures are effective. The marked increases in infections caused by some Salmonella serotypes provide an opportunity to investigate food and nonfood sources of infection and to design specific interventions.

FoodNet conducts active, population-based surveillance for laboratory-diagnosed infections caused by Campylobacter, Cryptosporidium, Cyclospora, Listeria, Salmonella, STEC, Shigella, Vibrio, and Yersinia in 10 sites that account for approximately 15% of the U.S. population (an estimated 49 million persons in 2016). FoodNet is a collaboration among CDC, 10 state health departments, the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA-FSIS), and the Food and Drug Administration (FDA). Laboratory-diagnosed bacterial infections are defined as isolation of bacteria from a clinical specimen by culture or detection by a CIDT. CIDTs detect bacterial antigens, nucleic acid sequences, or, for STEC, Shiga toxin or Shiga toxin genes.¶ A CIDT-positive–only bacterial infection is a positive CIDT result without culture confirmation. Listeria cases are defined as isolation of L. monocytogenes or detection by a CIDT from a normally sterile site or from placental or fetal tissue in the instance of miscarriage or stillbirth. Laboratory-diagnosed parasitic infections are defined as detection of the parasite from a clinical specimen. Hospitalizations and deaths within 7 days of specimen collection are attributed to the infection. Surveillance for physician-diagnosed postdiarrheal hemolytic uremic syndrome (HUS) is conducted through a network of nephrologists and infection preventionists and hospital discharge data review. This report includes pediatric HUS cases identified during 2016, the most recent year for which data are available.

Incidence per 100,000 population was calculated by dividing the number of infections in 2017 by the U.S. Census estimates of the surveillance area population for 2016. Incidence measures include all laboratory-diagnosed infections reported. A negative binomial model with 95% confidence intervals (CIs) was used to estimate change in incidence during 2017 compared with that during 2014–2016 and 2006–2008. Because of large changes in testing practices since 2006, incidence comparisons with 2006–2008 used only culture-confirmed bacterial infections, and comparisons with 2014–2016 used culture-confirmed and CIDT-positive–only cases combined. For HUS, 2016 incidence was compared with that during 2013–2015.

Preliminary incidence and trends of infections with pathogens transmitted commonly through food-foodborne diseases active surveillance network, 10 U.S. sites, 2006-2017

CDC

Ellyn Marder

https://www.cdc.gov/mmwr/volumes/67/wr/mm6711a3.htm

Acknowledgments

Workgroup members, Foodborne Diseases Active Surveillance Network (FoodNet), Emerging Infections Program, CDC; Brittany Behm, Staci Dixon, Elizabeth Greene, Logan Ray, Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, CDC; Neal Golden, Steven Mamber, and Joanna Zablotsky Kufel, U.S. Department of Agriculture’s Food Safety and Inspection Service.

Sick food handlers are a food safety risk

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A while back I was awarded a contract to teach food safety in correctional institutions. I clearly remember an incident when I was talking about not going to work when you are ill as this poses a food safety risk and I went to explain why. Then this massive looking dude about the size of Terry Crews jumps out of his seat yelling at me. Apparently he had worked in the food service industry and had to support a family of five without having any sick time. So, when he was sick he went to work. Thereafter it was blur as 5 correctional officers jumped in the room to detain my friend as I soiled myself from fear…

Heather Williams writes

We put a lot of trust in the people who prepare and serve our food. We expect that our food is safe to eat and handled appropriately. In the United States, we have standards for food safety and many regulations in place. Why wouldn’t we trust those who prepare and serve our food? Unfortunately, a significant number of food workers have admitted to working while knowingly being sick. There are many reasons someone might do this. Some do it for financial reasons, others for sense of duty, and then there are some who fear they may lose their job if they do not cover their shift. Could foodborne illness cases dramatically decrease if food workers could have sick leave, which would allow them monetary compensation for identifying their illness and not passing it on to other unsuspecting patrons? Let’s explore this.
Restaurants Are a Primary Source of Foodborne Outbreaks
According to the Center for Disease Control and Prevention (CDC), an estimated 48 million people become ill in the United States each year from foodborne infection. Approximately 128,000 are hospitalized and foodborne illness claims about 3,000 lives each year. Over half of all foodborne outbreaks reported to the CDC can be linked back to eating in restaurants or delicatessens.
In one study, a group of investigators gathered data from FoodNet. This resource is also known as the Foodborne Diseases Active Surveillance Network, a central database where participating sites report information regarding foodborne illness. In a study analyzing 457 foodborne disease outbreaks, 300 were restaurant related. 98% of the 300 had only one contributing factor causing the outbreak. The most common contributing factor resulting in 137 outbreaks was “handling by an infected person or carrier of pathogen.” This is a significant number considering one lapse can have such high statistical repercussions.
The purpose of the study was to identify the contributing factors in restaurant-linked foodborne disease outbreaks. 75% of the outbreaks investigated were linked to Norovirus and Salmonella. These infections were predominately linked back to transmission by food workers. Significant resources are devoted to preventing contamination of food products before they make it to the point of service. Restaurants must ensure that staff have adequate training and understanding for how to handle the food once it becomes in their custody. Food worker health and hygiene were primary factors in contributing to foodborne illness.

The rest of the story can be found be here:

http://www.unsafefoods.com/2017/08/29/sick-leave-reduce-foodborne-illness/

 

Kids, kids: Foodnet report is out

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It’s my favorite day of the year: The annual U.S. Foodnet report, where data is presented, mulled over, and then crammed into politically suitable food safety fairytales.

When a scientific report leads with, “The incidence of infections transmitted commonly through food has remained largely unchanged for many years,” isn’t it time to try something different?

The U.S. Centers for Disease Control reports reducing foodborne illness depends in part on identifying which illnesses are decreasing and which are increasing. Yet recent changes in the use of tests that diagnose foodborne illness pose challenges to monitoring illnesses and progress toward preventing foodborne disease, according to a report published today in CDC’s Morbidity and Mortality Weekly Report.

Rapid diagnostic tests help doctors diagnose infections quicker than traditional culture methods, which require growing bacteria to determine what is causing illness. But without a bacterial culture, public health officials cannot get the detailed information needed to detect and prevent outbreaks, monitor disease trends, and identify antibiotic resistance.

The MMWR article includes the most recent data from CDC’s Foodborne Diseases Active Surveillance Network, or FoodNet, which collects data on 15% of the U.S. population. It summarizes preliminary 2016 data on nine germs spread commonly through food. In 2016, FoodNet reported 24,029 infections, 5,512 hospitalizations, and 98 deaths. This is the first time the numbers used for calculations of trends include bacterial infections diagnosed only by rapid diagnostic tests as well as those confirmed by traditional culture-based methods. Previously, these calculations used only those bacterial infections confirmed by culture-based methods. The most frequent causes of infection in 2016 were Salmonella and Campylobacter, which is consistent with previous years.

 Incidence and Trends of Infections with Pathogens Transmitted Commonly Through Food and the Effect of Increasing Use of Culture-Independent Diagnostic Tests on Surveillance — Foodborne Diseases Active Surveillance Network, 10 U.S. Sites, 2013–2016

Marder EP, Cieslak PR, Cronquist AB, et al.

MMWR Morb Mortal Wkly Rep 2017;66:397–403. DOI: http://dx.doi.org/10.15585/mmwr.mm6615a1

https://www.cdc.gov/mmwr/volumes/66/wr/mm6615a1.htm?s_cid=mm6615a1_e#suggestedcitation

The incidence of infections transmitted commonly through food has remained largely unchanged for many years. Culture-independent diagnostic tests (CIDTs) are increasingly used by clinical laboratories to detect enteric infections.

What is added by this report?

Compared with the 2013–2015 average annual incidence, the 2016 incidence of confirmed Campylobacter infections was lower, incidences of confirmed Shiga toxin-producing Escherichia coli (STEC), Yersinia, and Cryptosporidium infections were higher, and incidences of confirmed or CIDT positive–only STEC and Yersinia infections were higher. However, CIDTs complicate the interpretation of surveillance data; testing for pathogens might occur more frequently because of changes in either health care provider behaviors or laboratory testing practices. A large proportion of CIDT positive specimens were not reflex cultured, which is necessary to obtain isolates for distinguishing pathogen subtypes, determining antimicrobial resistance, monitoring trends, and detecting outbreaks.

What are the implications for public health practice?

Some information about the bacteria causing infections, such as subtype and antimicrobial susceptibility, can only be obtained for CIDT positive specimens if reflex culture is performed. Increasing use of CIDTs affects the interpretation of public health surveillance data and ability to monitor progress toward prevention measures.

Foodborne diseases represent a substantial public health concern in the United States. CDC’s Foodborne Diseases Active Surveillance Network (FoodNet) monitors cases reported from 10 U.S. sites* of laboratory-diagnosed infections caused by nine enteric pathogens commonly transmitted through food. This report describes preliminary surveillance data for 2016 on the nine pathogens and changes in incidences compared with 2013–2015. In 2016, FoodNet identified 24,029 infections, 5,512 hospitalizations, and 98 deaths caused by these pathogens. The use of culture-independent diagnostic tests (CIDTs) by clinical laboratories to detect enteric pathogens has been steadily increasing since FoodNet began surveying clinical laboratories in 2010 (1). CIDTs complicate the interpretation of FoodNet surveillance data because pathogen detection could be affected by changes in health care provider behaviors or laboratory testing practices (2). Health care providers might be more likely to order CIDTs because these tests are quicker and easier to use than traditional culture methods, a circumstance that could increase pathogen detection (3). Similarly, pathogen detection could also be increasing as clinical laboratories adopt DNA-based syndromic panels, which include pathogens not often included in routine stool culture (4,5). In addition, CIDTs do not yield isolates, which public health officials rely on to distinguish pathogen subtypes, determine antimicrobial resistance, monitor trends, and detect outbreaks. To obtain isolates for infections identified by CIDTs, laboratories must perform reflex culture†; if clinical laboratories do not, the burden of culturing falls to state public health laboratories, which might not be able to absorb that burden as the adoption of these tests increases (2). Strategies are needed to preserve access to bacterial isolates for further characterization and to determine the effect of changing trends in testing practices on surveillance.

FoodNet is a collaboration among CDC, 10 state health departments, the U.S. Department of Agriculture’s Food Safety and Inspection Service, and the Food and Drug Administration. FoodNet personnel conduct active, population-based surveillance for laboratory-diagnosed infections caused by Campylobacter, Cryptosporidium, Cyclospora, Listeria, Salmonella, Shiga toxin-producing Escherichia coli (STEC), Shigella, Vibrio, and Yersinia for 10 sites covering approximately 15% of the U.S. population (an estimated 49 million persons in 2015). Confirmed bacterial infections are defined as isolation of the bacterium from a clinical specimen by culture. Confirmed parasitic infections are defined as detection of the parasite from a clinical specimen by direct fluorescent antibody test, polymerase chain reaction, enzyme immunoassay, or light microscopy. CIDTs detect bacterial pathogen antigen, nucleic acid sequences, or for STEC, Shiga toxin or Shiga toxin genes, in a stool specimen or enrichment broth.§ A CIDT positive–only bacterial infection is a positive CIDT result that was not confirmed by culture. Hospitalizations occurring within 7 days of specimen collection are recorded. The patient’s vital status at hospital discharge (or 7 days after specimen collection if not hospitalized) is also recorded. Hospitalizations and deaths occurring within 7 days of specimen collection are attributed to the infection. FoodNet also conducts surveillance for physician-diagnosed postdiarrheal hemolytic uremic syndrome (HUS), a potential complication of STEC infection, by review of hospital discharge data through a network of nephrologists and infection preventionists. This report includes HUS cases among persons aged <18 years for 2015, the most recent year with available data.

Incidence of infection for each pathogen is calculated by dividing the number of infections in 2016 by the U.S. Census estimates of the surveillance area population for 2015. Incidence is calculated for confirmed infections alone and for confirmed or CIDT positive–only infections combined. A negative binomial model with 95% confidence intervals (CIs) was used to estimate changes in incidence of confirmed bacterial and parasitic infections and confirmed or CIDT positive–only bacterial infections in 2016 compared with 2013–2015, adjusting for changes in the surveillance population over time. For STEC, incidence is reported for all STEC serogroups combined because it is not possible to distinguish between serogroups using CIDTs. Insufficient data were available to assess change for Cyclospora. For HUS, the 2015 incidence was compared with incidence during 2012–2014.

Cases of Infection, Incidence, and Trends

During 2016, FoodNet identified 24,029 cases, 5,512 hospitalizations, and 98 deaths caused by confirmed or CIDT positive–only infections. The largest number of confirmed or CIDT positive–only infections in 2016 was reported for Campylobacter (8,547), followed by Salmonella (8,172), Shigella (2,913), STEC (1,845), Cryptosporidium (1,816), Yersinia (302), Vibrio (252), Listeria (127), and Cyclospora (55). The proportion of infections that were CIDT positive without culture confirmation in 2016 was largest for Campylobacter (32%) and Yersinia (32%), followed by STEC (24%), Shigella (23%), Vibrio (13%), and Salmonella (8%). The overall increase in CIDT positive–only infections for these six pathogens in 2016 was 114% (range = 85%–1,432%) compared with 2013–2015. Among infections with a positive CIDT result in 2016, a reflex culture was attempted on approximately 60% at either a clinical or state public health laboratory. The proportion of attempted reflex cultures differed by pathogen, ranging from 45% for Campylobacter to 86% for STEC and 88% for Vibrio. Among infections for which reflex culture was performed, the proportion of infections that were positive was highest for Salmonella (88%) and STEC (87%), followed by Shigella (64%), Yersinia (59%), Campylobacter (52%), and Vibrio (46%).

The incidence of confirmed infections and of confirmed or CIDT positive–only infections per 100,000 persons was highest for Campylobacter (confirmed = 11.79; confirmed or CIDT positive–only = 17.43) and Salmonella (15.40; 16.66), followed by Shigella (4.60; 5.94), Cryptosporidium (3.64; N/A**), STEC (2.85; 3.76), Yersinia (0.42; 0.62), and lowest for Vibrio (0.45; 0.51), Listeria (0.26; N/A), and Cyclospora (0.11; N/A). Compared with 2013–2015, the 2016 incidence of Campylobacter infection was significantly lower (11% decrease) when including only confirmed infections, yet was not significantly different when including confirmed or CIDT positive–only infections. Incidence of STEC infection was significantly higher for confirmed infections (21% increase) and confirmed or CIDT positive–only infections (43% increase). Similarly, the incidence of Yersinia infection was significantly higher for both confirmed (29% increase) and confirmed or CIDT positive–only infections (91% increase). Incidence of confirmed Cryptosporidium infection was also significantly higher in 2016 compared with 2013–2015 (45% increase).

Among 7,554 confirmed Salmonella cases in 2016, serotype information was available for 6,583 (87%). The most common serotypes were Enteritidis (1,320; 17%), Newport (797; 11%), and Typhimurium (704; 9%). The incidence in 2016 compared with 2013–2015 was significantly lower for Typhimurium (18% decrease; CI = 7%–21%) and unchanged for Enteritidis and Newport. Among 208 (95%) speciated Vibrio isolates, 103 (50%) were V. parahaemolyticus, 35 (17%) were V. alginolyticus, and 26 (13%) were V. vulnificus. Among 1,394 confirmed and serogrouped STEC cases, 503 (36%) were STEC O157 and 891 (64%) were STEC non-O157. Among 586 (70%) STEC non-O157 isolates, the most common serogroups were O26 (190; 21%), O103 (178; 20%), and O111 (106; 12%). Compared with 2013–2015, the incidence of STEC non-O157 infections in 2016 was significantly higher (26% increase; CI = 9%–46%) and the incidence of STEC O157 was unchanged.

FoodNet identified 62 cases of postdiarrheal HUS in children aged <18 years (0.56 cases per 100,000) in 2015; 33 (56%) occurred in children aged <5 years (1.18 cases per 100,000). Compared with 2012–2014, in 2015, no significant differences in incidence among all children or children aged <5 years were observed.

Discussion

The number of CIDT positive–only infections reported to FoodNet has been increasing markedly since 2013, as more clinical laboratories adopt CIDTs. Initially, increases were primarily limited to Campylobacter and STEC; followed by substantial increases in Salmonella and Shigella beginning in 2015 (6). The pattern continued in 2016, with large increases in the number of CIDT positive–only Vibrio and Yersinia infections. When including both confirmed and CIDT positive–only infections, incidence rates in 2016 were higher for each of these six pathogens. The increasing use of CIDTs presents challenges when interpreting the corresponding increases in incidence. For example, the incidence of confirmed Campylobacter infections in 2016 was significantly lower than the 2013–2015 average. However, when including CIDT positive–only infections, a slight but not significant increase occurred. For STEC and Yersinia, the incidence of confirmed infections alone and confirmed or CIDT positive–only infections in 2016 were both significantly higher than the 2013–2015 average; the magnitude of change approximately doubled when analyzing CIDT positive–only infections.

Because of the ease and increasing availability of CIDTs, testing for some pathogens might be increasing as health care provider behaviors and laboratory practices evolve (2). Among clinical laboratories in the FoodNet catchment, the use of CIDTs to detect Salmonella, for which the only CIDTs available are DNA-based gastrointestinal syndrome panels, increased from 2 per 460 laboratories (<1%) in 2013 to 59 per 421 laboratories (14%) in 2016 (FoodNet, unpublished data). This increased use paralleled significant increases in incidence of Cryptosporidium, STEC, and Yersinia, and slight but not significant increases in incidence of Campylobacter, Salmonella, Shigella, and Vibrio, all of which are also included in these panel tests. The increase in STEC incidence is driven by the increase in STEC non-O157, which is not typically included in routine stool culture testing because it requires specialized methods. Routine stool cultures performed in clinical laboratories typically include methods that identify only Salmonella, Campylobacter, Shigella, and for some laboratories, STEC O157 (4,5). The increased use of the syndrome panel tests might increase identification, and thus, improve incidence estimates of pathogens for which testing was previously limited.

Results are more quickly obtained using CIDTs than traditional culture methods (3). Because of this, health care providers might be more likely to order a CIDT than traditional culture (2). Increased testing might identify infections that previously would have remained undiagnosed. However, sensitivity and specificity vary by test type. Evaluations of DNA-based syndrome panel tests have indicated high sensitivity and specificity for most targets (3). However, among pathogens for which antigen-based CIDTs are often used, such as Campylobacter and Cryptosporidium, sensitivity and specificity have varied more widely, with a large number of false positive results (7,8). Including CIDT positive infections to calculate incidence, some of which could be false positives, might provide an inaccurate estimate. When interpreting incidence and trends in light of changing diagnostic testing, considering frequency of testing, sensitivity, and specificity of these tests is important. The observed increases in incidence of confirmed or CIDT positive–only infections in 2016 compared with 2013–2015 could be caused by increased testing, varying test sensitivity, an actual increase in infections, or a combination of these reasons.

These changes in testing are also important to consider when monitoring progress toward Healthy People 2020 objectives.†† The current objectives were created before the use of CIDTs and were based on confirmed infections. In the future, just as incidence measures should adjust for these changes, objectives should also be evaluated in light of changing diagnostics.

CIDTs pose additional challenges because they do not yield the bacterial isolates necessary for essential public health surveillance activities, such as monitoring trends in pathogen subtypes, conducting molecular testing, detecting outbreaks and implicating vehicles, and determining antimicrobial susceptibility. Reflex culture performed to yield an isolate places an additional burden on laboratories’ budgets, personnel, and time. Specimen submission requirements differ by state and pathogen, and this responsibility often falls to state public health laboratories (9). As CIDT use increases and more pathogens are affected, state public health laboratories will be challenged to sufficiently increase their testing capacity and will likely have to prioritize specimens on which to perform reflex culture (10). Clinical laboratories should review state specimen submission requirements and the Association of Public Health Laboratories guidelines§§ for reflex culture and submission of CIDT positive specimens.

The findings in this report are subject to at least two limitations. First, the changing diagnostic landscape with unknown changes in frequency of testing, varying test performance, and decreasing availability of isolates for subtyping make interpreting incidence and trends more difficult. Second, changes in health care–seeking behavior, access to health services, or other population characteristics might have changed since the comparison period, which could affect incidence.

Foodborne illness remains a substantial public health concern in the United States. Previous analyses have indicated that the number of infections far exceeds those diagnosed; CIDTs might be making those infections more visible (11). Most foodborne infections can be prevented, and substantial progress has been made in the past in decreasing contamination of some foods and reducing illness caused by some pathogens. More prevention measures are needed. Surveillance data can provide information on where to target these measures. However, to accurately interpret FoodNet surveillance data in light of changes in diagnostic testing, more data and analytic tools are needed to adjust for changes in testing practices and differences in test characteristics. FoodNet is collecting more data and developing those tools. With these, FoodNet will continue to track the needed progress toward reducing foodborne illness.

Acknowledgments

Foodborne Diseases Active Surveillance Network staff members, Emerging Infections Program; Brittany Behm, Staci Dixon, Elizabeth Greene, Jennifer Huang, Clare Wise, and FoodNet Fast Development Team, Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, CDC.

Sporadic illnesses, outbreak illnesses, are similiar

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Outbreak data have been used to estimate the proportion of illnesses attributable to different foods. Applying outbreak-based attribution estimates to non-outbreak foodborne illnesses requires an assumption of similar exposure pathways for outbreak and sporadic illnesses. This assumption cannot be tested, but other comparisons can assess its veracity.

vomit-FBOur study compares demographic, clinical, temporal, and geographic characteristics of outbreak and sporadic illnesses from Campylobacter, Escherichia coli O157, Listeria, and Salmonella bacteria ascertained by the Foodborne Diseases Active Surveillance Network (FoodNet). Differences among FoodNet sites in outbreak and sporadic illnesses might reflect differences in surveillance practices. For Campylobacter, Listeria, and Escherichia coli O157, outbreak and sporadic illnesses are similar for severity, sex, and age. For Salmonella, outbreak and sporadic illnesses are similar for severity and sex. Nevertheless, the percentage of outbreak illnesses in the youngest age category was lower.

Therefore, we do not reject the assumption that outbreak and sporadic illnesses are similar.

Comparing characteristics of sporadic and outbreak-associated foodborne illnesses, United States, 2004-2011

Emerging Infectious Diseases, Volume 22, Number 7, July 2016, DOI: 0.3201/eid2207.150833

E.D. Ebel, M.S. Williams, D. Cole, C.C. Travis, K.C. Klontz, N.J. Golden, R.M. Hoekstra

http://wwwnc.cdc.gov/eid/article/22/7/15-0833_article

Campy up, E. coli O157 down: Foodborne diseases active surveillance network (FoodNet)

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The U.S. Centers for Disease Control and Prevention Foodborne Diseases Active Surveillance Network, or FoodNet, has been tracking trends for infections transmitted commonly through food since 1996.

cdc.food.safety.14FoodNet provides a foundation for food safety policy and prevention efforts. It estimates the number of foodborne illnesses, monitors trends in incidence of specific foodborne illnesses over time, attributes illnesses to specific foods and settings, and disseminates this information.

“FoodNet has matured and transformed over 20 years, and continues to evolve as technologies change,” says Dr. Olga Henao, FoodNet Team Lead.

The Foodborne Diseases Active Surveillance Network, or FoodNet, has been tracking trends in foodborne infections since 1996.

FoodNet provides a foundation for food safety policy and prevention efforts by estimating the number of foodborne illnesses, monitoring trends of specific foodborne illnesses, conducting studies to understand the causes of these illnesses, and informing the public about its findings.

FoodNet began to collect information on two pathogen cases identified by CIDT in 2009 and expanded the collection to other pathogens in 2011.

FoodNet has conducted surveillance for laboratory-confirmed cases of infection in humans  caused by Campylobacter, Listeria, Salmonella, Shiga toxin-producing E. coli (STEC) O157,  Shigella, Vibrio, and Yersinia since 1996, Cryptosporidium and Cyclospora since 1997, and STEC non-O157 since 2000. FoodNet staff in state health departments contact clinical laboratories in the surveillance area to get reports of infections diagnosed in residents.

Special Studies

Although foodborne outbreaks are common, most foodborne infections are sporadic, meaning they are not related to an outbreak. We can only rarely determine how one person got an infection but, by studying a large number of people with the same type of infection, we can often determine risk factors for getting ill.

Major Contributions

FoodNet is the only U.S. system focused on obtaining comprehensive information about sporadic infections caused by pathogens transmitted commonly through food. The network’s contributions to food safety policy and illness prevention include:

Establishing reliable, active population-based surveillance to understand who gets sick and why;

Developing and implementing studies that determine risk and protective factors for foodborne infections;

Conducting population surveys and laboratory surveys that describe the features of gastrointestinal illnesses, medical care-seeking behavior, foods eaten, and laboratory practices; and

Improving our ability at the federal and state level to track and study foodborne illnesses and respond to new issues as they arise. 

About FoodNet

Surveillance in an area that includes 15% of the U.S. population (approximately 48 million people)

Collaboration among CDC, 10 state health departments, the U.S. Department of Agriculture’s Food Safety and Inspection Service, and the Food and Drug Administration. (Image: U.S. map showing FoodNet sites.)

Principal foodborne disease component of CDC’s Emerging Infections Program

Provides the data necessary for measuring the progress in foodborne disease prevention.

Foodborne Diseases Active Surveillance Network—2 decades of achievements, 1996–2015

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The Foodborne Diseases Active Surveillance Network (FoodNet) provides a foundation for food safety policy and illness prevention in the United States.

FoodNet.pyramid.fbi.OverviewFoodNet conducts active, population-based surveillance at 10 US sites for laboratory-confirmed infections of 9 bacterial and parasitic pathogens transmitted commonly through food and for hemolytic uremic syndrome.

Through FoodNet, state and federal scientists collaborate to monitor trends in enteric illnesses, identify their sources, and implement special studies. FoodNet’s major contributions include establishment of reliable, active population-based surveillance of enteric diseases; development and implementation of epidemiologic studies to determine risk and protective factors for sporadic enteric infections; population and laboratory surveys that describe the features of gastrointestinal illnesses, medical care–seeking behavior, frequency of eating various foods, and laboratory practices; and development of a surveillance and research platform that can be adapted to address emerging issues.

The importance of FoodNet’s ongoing contributions probably will grow as clinical, laboratory, and informatics technologies continue changing rapidly.

Foodborne Diseases Active Surveillance Network—2 decades of achievements, 1996–2015

Emerging Infectious Diseases, Volume 21, Number 9,  September 2015

Olga L. Henao Comments to Author , Timothy F. Jones, Duc J. Vugia, Patricia M. Griffin, and for the Foodborne Diseases Active Surveillance Network (FoodNet) Workgroup

http://wwwnc.cdc.gov/eid/article/21/9/15-0581_article