Elaine Scallan Walter

Background: Listeriosis is a severe foodborne illness with elevated incidence rates among pregnant women, older adults, individuals with medical comorbidities, and certain racial and ethnic subpopulations. Foodborne Diseases Active Surveillance Network (FoodNet) data allow examination of incidence trends and differences. Methods: We analyze sporadic invasive listeriosis cases reported to FoodNet from 2008 to 2023. Incidence rates and rate ratios are calculated overall and by studied period, pregnancy status, age, sex, race, and ethnicity. US Census Bureau demographic projections are used to estimate incidence rate changes expected from changes in the structure of the population with time. Results: The overall incidence rate of domestically acquired sporadic listeriosis has remained stable in the FoodNet catchment area over the 15-year period, with a latest estimate (2020–2023) of 0.25 (95% confidence interval [95% CI, .22–.30) per 100 000 person-years. No significant temporal trend in any studied subpopulation is observed. Pregnant women have a 64-fold (95% CI, 47–87) higher risk when compared to non-pregnant women of reproductive age. Incidence rate in the non-pregnant population rises with age, and Hispanic, non-Hispanic Asian, and non-Hispanic Black populations have higher rates than non-Hispanic White populations. An increased overall incidence rate would have been expected because of demographic shifts; instead, the observed stable incidence rate suggests approximately 16% lower exposure to Listeria monocytogenes in 2023 compared with 2008. Conclusions: Stable listeriosis incidence rates despite demographic shifts suggest reduced population exposure to L monocytogenes. Targeted prevention for disproportionately affected subpopulations, alongside continued efforts to reduce exposure broadly, is needed to further reduce the risk of invasive listeriosis.

Background: Foodborne diseases cause substantial global morbidity and mortality, yet remain largely unattended. To support countries to address this public health concern, the World Health Assembly Resolution 73.5 called for strengthening global food safety efforts and led to the development of the WHO Global Strategy for Food Safety 2022–2030, adopted at the 75th WHA (2022). To this end, the World Health Organization (WHO) reconvened the Foodborne Disease Burden Epidemiology Reference Group (FERG) to advise and support the work to generate updated global, regional, and national estimates of the foodborne disease burden for the reference period 2000–2021. Methods: We developed an incidence-based framework expanding coverage to 42 foodborne hazards. Standardized systematic reviews, Global Health Estimates and Global Burden of Disease envelopes, and United Nations population data informed the evidence base. Missing epidemiological data were imputed using Bayesian hierarchical meta-regression models. Disease models mapped acute and chronic health outcomes, applying updated disability weights, life tables, and probabilistic Monte Carlo calculations to estimate incidence, mortality, Years Lived with Disability, Years of Life Lost and Disability-Adjusted Life Years for all 194 WHO Member States. Transparency and analysis reproducibility were ensured through availed open source R packages and standardized workflows. Results: The computational framework provides annual, country-level estimates with improved internal consistency and an expanded hazard scope compared with the WHO 2015 edition. Advances include refined modelling, enhanced uncertainty propagation, and broader inclusion of microbial, parasitic, and chemical hazards. Persistent data gaps—especially in high-burden regions—were filled through extensive imputation. Conclusions: The computational framework for the WHO 2026 edition delivers the most comprehensive and transparent assessment of the global burden of foodborne diseases to date. Despite remaining limitations, it enables routine monitoring, supports evaluation of global food safety efforts, and highlights priorities for strengthening national data systems.

Diarrheal disease is caused by diverse species of viruses, bacteria and protozo that are transmitted from different sources, including from contaminated food. Sustaining progress in reducing diarrheal illnesses and deaths, including vaccines and food safety measures, may require interventions targeting specific pathogens. In 2015, the WHO’s published etiology-specific estimates by their Foodborne Disease Burden Epidemiology Reference Group (FERG) of the incidence and mortality of diarrheal diseases caused by 11 pathogens at global and regional scales in 2010. Since then, much new evidence has been published about the epidemiology of enteropathogens. This study aims to update estimates to the year 2021 with the addition of three pathogens (Rotavirus, Cyclospora cayetanensis , Enteroaggregative E. coli (EAEC)). For low- and middle-income countries (LMICs), we conducted a systematic review of publications that reported the prevalence of pathogens diagnosed in stool samples from asymptomatic subjects, community-detected and outpatient diarrhea cases, and those treated as inpatients. Hierarchical, mixed effects models were fitted to pathogen-specific prevalence data extracted from studies that met prespecified inclusion criteria, and population attributable fractions (PAF) were calculated from the model parameter estimates, adjusting for background asymptomatic transmission where appropriate. The PAFs were applied to previously estimated diarrhea incidence and mortality envelopes. A separate, parallel systematic review identified studies that estimated diarrhea incidence and mortality due to specific etiologies for high income countries (HICs) from surveillance data. Meta-analytical models were fitted to data extracted from these. Data from 324 studies published between 1990 and 2023 representing results from up to 540,000 samples were used in the meta-analysis. Globally the 14 pathogens were responsible for 2.2 billion diarrheal disease cases and 880,000 deaths in 2021, with the largest number of cases occurring in South-East Asia, the largest number of deaths in Sub-Saharan Africa, and Europe being the region with the lowest burden by both measures. We found the leading causes of diarrhea morbidity to be bacteria – Shigella (426.4 million cases in 2021), Campylobacter (291.4 million) and ETEC (259.7 million)) – as well as the protozoon Giardia (321.2 million), in contrast to previous studies that have ranked rotavirus and norovirus highest. Our estimates support a much higher morbidity burden for Shigella than previously estimated with an incidence rate for 2021 (5,400 per 100,000). This is due to its high PAF in outpatients aged ≥5 years. As causes of diarrhea mortality, our estimates rank rotavirus first (214,700 deaths in 2021), Shigella second (152,500), and V. cholerae (94,100) third, due to the latter’s large PAF in inpatients aged ≥5 years and high case fatality rate. Caution is urged when interpreting PAFs for pathogens that elicit prolonged residual shedding following resolution of symptoms (e.g., norovirus, Campylobacter , Giardia ). These findings, derived from rigorous systematic review and statistical methodologies and the largest database yet compiled of pathogen detection rates, will serve as inputs for the WHO’s broader estimates of hazard-specific incidence and mortality from foodborne diseases and are made available to the research and policy-making communities to inform targeted strategies for global diarrheal disease control. Funding: WHO EDTF_001; 1K01AI168493-01A1; K43TW012298; 5T32AI007046-48.

Foodborne Illness in the United States, 2019

Foodborne disease burden estimates inform public health priorities and can help the public understand disease impact. This article provides new estimates of the cost of U.S. foodborne illness. Our research updated disease modeling underlying these cost estimates with a focus on enhancing chronic sequelae modeling and enhancing uncertainty modeling. Our cost estimates were based on U.S. Centers for Disease Control and Prevention estimates of the numbers of foodborne illnesses, hospitalizations, and deaths caused by 31 known foodborne pathogens and unspecified foodborne agents. We augmented these estimates of illnesses, hospitalizations, and deaths with more detailed modeling of health outcomes, including chronic sequelae. For health outcomes, we relied on U.S. data and research where possible, supplemented by the use of non-U.S. research where necessary and scientifically appropriate. Cost estimates were developed from large insurance or hospital charge databases, public data sources, and existing literature and were adjusted to 2023 dollars. We estimated the cost of foodborne illness in the United States circa 2023 to be $75 billion. Deaths accounted for 56% and chronic outcomes for 31% of the mean cost. The costliest pathogen was nontyphoidal Salmonella at $17.1 billion followed by Campylobacter at $11.3 billion. Toxoplasma ($5.7 billion) and Listeria ($4 billion) followed due primarily to deaths and chronic outcomes from pregnancy-associated cases. Per-case cost ranged from $196 for Bacillus cereus to $4.6 million for Vibrio vulnificus. Unspecified agents accounted for 38% of the total cost of foodborne illness, but these illnesses were generally mild (per-case cost $781). These cost estimates can help inform food safety priorities. Our pathogen-specific per-case cost estimates can also help inform benefit–cost analysis required for new federal food safety regulations.