Attribution of country level foodborne disease to food group and food types in three African countries: Conclusions from a structured expert judgment study

Abstract

Background According to the World Health Organization, 600 million cases of foodborne disease occurred in 2010. To inform risk management strategies aimed at reducing this burden, attribution to specific foods is necessary. Objective We present attribution estimates for foodborne pathogens (Campylobacter spp., enterotoxigenic Escherichia coli (ETEC), Shiga-toxin producing E. coli, nontyphoidal Salmonella spp., Cryptosporidium spp., Brucella spp., and Mycobacterium bovis) in three African countries (Burkina Faso, Ethiopia, Rwanda) to support risk assessment and cost-benefit analysis in three projects aimed at increasing safety of beef, dairy, poultry meat and vegetables in these countries. Methods We used the same methodology as the World Health Organization, i.e., Structured Expert Judgment according to Cooke’s Classical Model, using three different panels for the three countries. Experts were interviewed remotely and completed calibration questions during the interview without access to any resources. They then completed target questions after the interview, using resources as considered necessary. Expert data were validated using two objective measures, calibration score or statistical accuracy, and information score. Performance-based weights were derived from the two measures to aggregate experts’ distributions into a so-called decision maker. The analysis was made using Excalibur software, and resulting distributions were normalized using Monte Carlo simulation. Results Individual experts’ uncertainty assessments resulted in modest statistical accuracy and high information scores, suggesting overconfident assessments. Nevertheless, the optimized item-weighted decision maker was statistically accurate and informative. While there is no evidence that animal pathogenic ETEC strains are infectious to humans, a sizeable proportion of ETEC illness was attributed to animal source foods as experts considered contamination of food products by infected food handlers can occur at any step in the food chain. For all pathogens, a major share of the burden was attributed to food groups of interest. Within food groups, the highest attribution was to products consumed raw, but processed products were also considered important sources of infection. Conclusions Cooke’s Classical Model with performance-based weighting provided robust uncertainty estimates of the attribution of foodborne disease in three African countries. Attribution estimates will be combined with country-level estimates of the burden of foodborne disease to inform decision making by national authorities.

Burden of foodborne disease due to bacterial hazards associated with beef, dairy, poultry meat, and vegetables in Ethiopia and Burkina Faso, 2017

“…Estimates of the proportion of FBD incidence associated with CAMP and NTS were attributed to beef, dairy, poultry meat and vegetables based on FERG attribution results for the AFRD and AFRE subregions (Hoffmann et al, 2017) as described by Li et al (2019). Attribution to food types and food products (see Sapp et al, 2022 for details) were based on a structured expert judgment study organized specifically for this study according to Cooke's Classical Model (Cooke, 1992;Hald et al, 2016). This study also included food group attribution for ETEC as these have not been provided by FERG, who focused their food group attribution on zoonotic pathogens.…”

“…Attribution estimates are described in detail in Sapp et al (2022). In this paper, we summarize the results for the four food groups of interest in the TARTARE and Pull Push projects: beef (Ethiopia), dairy (Ethiopia), poultry meat (Burkina Faso and Ethiopia) and vegetables (Burkina Faso and Ethiopia).…”

“…In this paper, we summarize the results for the four food groups of interest in the TARTARE and Pull Push projects: beef (Ethiopia), dairy (Ethiopia), poultry meat (Burkina Faso and Ethiopia) and vegetables (Burkina Faso and Ethiopia). The burden attributed to these different food groups was further attributed to specific food types and food products as defined in Sapp et al (2022). We present estimates for the total population only.…”

“…The objectives of this study are to update estimates of the burden of FBD for the pathogens selected by two projects in Ethiopia and Burkina Faso-TARTARE (TARTARE, 2018) and Pull-Push (International Livestock Research Institute, 2018) and estimate the burden associated with consuming food products selected for intervention in these projects. Further details on the objectives of these projects can be found in Sapp et al (2022).…”

Core Genome Sequencing Analysis of E. coli O157:H7 Unravelling Genetic Relatedness among Strains from Cattle, Beef, and Humans in Bishoftu, Ethiopia

“…In the United States, among 466 reported STEC outbreaks between 2010 and 2017 affecting 4769 persons, 20% of the outbreaks were linked to beef, and 71% of the outbreaks were caused by E. coli O157 [14]. Recently, in Ethiopia, a Structured Expert Elicitation study attributed about 60% of the burden of STEC in beef to red meat and about 31% to beef consumed raw [17].…”