Tag Archives: attribution

What foods are most likely to cause illness by shiga toxin-producing Escherichia coli (STEC) and how best to control secondary infections

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Two abstracts attempt to provide guidance to these important questions to reduce the toll of STEC.

FAO and WHO conclude shiga toxin-producing Escherichia coli (STEC) infections are a substantial public health issue worldwide, causing more than 1 million illnesses, 128 deaths and nearly 13 000 Disability-Adjusted Life Years (DALYs) annually.

To appropriately target interventions to prevent STEC infections transmitted through food, it is important to determine the specific types of foods leading to these illnesses.

An analysis of data from STEC foodborne outbreak investigations reported globally, and a systematic review and meta-analysis of case-control studies of sporadic STEC infections published for all dates and locations, were conducted. A total of 957 STEC outbreaks from 27 different countries were included in the analysis.

Overall, outbreak data identified that 16% (95% UI, 2-17%) of outbreaks were attributed to beef, 15% (95% UI, 2-15%) to produce (fruits and vegetables) and 6% (95% UI, 1-6%) to dairy products. The food sources involved in 57% of all outbreaks could not be identified. The attribution proportions were calculated by WHO region and the attribution of specific food commodities varied between geographic regions.

In the European and American sub-regions of the WHO, the primary sources of outbreaks were beef and produce (fruits and vegetables). In contrast, produce (fruits and vegetables) and dairy were identified as the primary sources of STEC outbreaks in the WHO Western Pacific sub-region.

The systematic search of the literature identified useable data from 21 publications of case-control studies of sporadic STEC infections. The results of the meta-analysis identified, overall, beef and meat-unspecified as significant risk factors for STEC infection. Geographic region contributed to significant sources of heterogeneity. Generally, empirical data were particularly sparse for certain regions.

Care must be taken in extrapolating data from these regions to other regions for which there are no data. Nevertheless, results from both approaches are complementary, and support the conclusion of beef products being an important source of STEC infections. Prioritizing interventions for control on beef supply chains may provide the largest return on investment when implementing strategies for STEC control.

Second up, in 2016, we reviewed preventive control measures for secondary transmission of Shiga-toxin producing Escherichia coli (STEC) in humans in European Union (EU)/European Free Trade Association (EEA) countries to inform the revision of the respective Norwegian guidelines which at that time did not accommodate for the varying pathogenic potential of STEC.

We interviewed public health experts from EU/EEA institutes, using a semi-structured questionnaire. We revised the Norwegian guidelines using a risk-based approach informed by the new scientific evidence on risk factors for HUS and the survey results.

All 13 (42%) participating countries tested STEC for Shiga toxin (stx) 1, stx2 and eae (encoding intimin). Five countries differentiated their control measures based on clinical and/or microbiological case characteristics, but only Denmark based their measures on routinely conducted stx subtyping. In all countries, but Norway, clearance was obtained with ⩽3 negative STEC specimens. After this review, Norway revised the STEC guidelines and recommended only follow-up of cases infected with high-virulent STEC (determined by microbiological and clinical information); clearance is obtained with three negative specimens.

Implementation of the revised Norwegian guidelines will lead to a decrease of STEC cases needing follow-up and clearance, and will reduce the burden of unnecessary public health measures and the socioeconomic impact on cases. This review of guidelines could assist other countries in adapting their STEC control measures.

Mapping of control measures to prevent secondary transmission of STEC infections in Europe during 2016 and revision of the national guidelines in Norway

Cambridge University Press vol. 147

  1. Veneti(a1)(a2), H. Lange (a1), L. Brandal (a1), K. Danis (a2) (a3) and L. Vold 

DOI: https://doi.org/10.1017/S0950268819001614
https://www.cambridge.org/core/journals/epidemiology-and-infection/article/mapping-of-control-measures-to-prevent-secondary-transmission-of-stec-infections-in-europe-during-2016-and-revision-of-the-national-guidelines-in-norway/1990D2338B220F80F0E683DF6F622A40

What foods make people sick? It’s complicated, so follow the bug

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Sometimes it’s best to let things ruminate, ferment, instead of simply repeating public relations drivel.

bob-carol-ted-alice-1969-2Guess that’s one reason people write books. Or journal articles.

Various U.S. government agencies patted themselves on the back for their “improved method for analyzing outbreak data to determine which foods are responsible for illness” while underselling the actual report.

ifsac-food-categories-508c
The U.S. Food and Drug Administration (FDA), the Centers for Disease Control and Prevention (CDC) and the USDA’s Food Safety and Inspection Service (FSIS) co-authored a report (and threesomes never work out well), Foodborne Illness Source Attribution Estimates for Salmonella, Escherichia coli O157 (E. coli O157), Listeria monocytogenes (Lm), and Campylobacter using Outbreak Surveillance Data by the Interagency Food Safety Analytics Collaboration (IFSAC). A partnership of the three agencies, IFSAC focuses on foodborne illness source attribution, which is the process of estimating the most common food sources responsible for specific foodborne illnesses.

The report briefly summarizes IFSAC’s methods and results, including estimated attribution percentages for the four pathogens named in its title. CDC estimates that, together, these four pathogens cause 1.9 million cases of foodborne illness in the United States each year.

The agencies anticipate that IFSAC’s work will enhance their efforts to prevent foodborne illness.

Who doesn’t anticipate what threesomes will bring.

food.attribution.fbi.feb.15The new estimates, combined with other data, may shape agency priorities and support the development of regulations and performance standards and measures, among other activities. The recently developed method employs new food categories that align with those used to regulate food products and emphasizes more recent outbreak data.

As outlined in the report, IFSAC analyzed data from nearly 1,000 outbreaks that occurred from 1998 to 2012 to assess which categories of foods were most responsible for making people sick with Salmonella, E. coli O157, Listeria, and Campylobacter. IFSAC experts divided food into 17 categories for the analysis. The pathogens were chosen because of the frequency or severity of the illnesses they cause, and because targeted interventions can have a significant impact in reducing them.

The report presents the methods behind the results and provides the amount of uncertainty around the estimates. 

Some of the findings include:

More than 80 percent of E. coli O157 illnesses were attributed to beef and vegetable row crops, such as leafy vegetables.

Salmonella illnesses were broadly attributed across food commodities, with 77 percent of illnesses related to seeded vegetables (such as tomatoes), eggs, fruits, chicken, beef, sprouts and pork.

Nearly 75 percent of Campylobacter illnesses were attributed to dairy (66 percent) and chicken (8 percent). Most of the dairy outbreaks used in the analysis were related to raw milk or cheese produced from raw milk, such as unpasteurized queso fresco.

More than 80 percent of Listeria illnesses were attributed to fruit (50 percent) and dairy (31 percent). Data were sparse for Listeria, and the estimate for fruit reflects the impact of a single large outbreak linked to cantaloupes in 2011.

The figure on the right (the one other than Bob, Carol, Ted and Alice) is what they sent out to PR types. The figure on the left is what they actually wrote.