Foodborne illness outbreaks linked to unpasteurised milk and relationship to changes in state laws - United States, 1998-2018.

Consumption of unpasteurised milk in the United States has presented a public health challenge for decades because of the increased risk of pathogen transmission causing illness outbreaks. We analysed Foodborne Disease Outbreak Surveillance System data to characterise unpasteurised milk outbreaks. Using Poisson and negative binomial regression, we compared the number of outbreaks and outbreak-associated illnesses between jurisdictions grouped by legal status of unpasteurised milk sale based on a May 2019 survey of state laws. During 2013-2018, 75 outbreaks with 675 illnesses occurred that were linked to unpasteurised milk; of these, 325 illnesses (48%) were among people aged 0-19 years. Of 74 single-state outbreaks, 58 (78%) occurred in states where the sale of unpasteurised milk was expressly allowed. Compared with jurisdictions where retail sales were prohibited (n = 24), those where sales were expressly allowed (n = 27) were estimated to have 3.2 (95% CI 1.4-7.6) times greater number of outbreaks; of these, jurisdictions where sale was allowed in retail stores (n = 14) had 3.6 (95% CI 1.3-9.6) times greater number of outbreaks compared with those where sale was allowed on-farm only (n = 13). This study supports findings of previously published reports indicating that state laws resulting in increased availability of unpasteurised milk are associated with more outbreak-associated illnesses and outbreaks.

Recency-Weighted Statistical Modeling Approach to Attribute Illnesses Caused by 4 Pathogens to Food Sources Using Outbreak Data, United States.

Foodborne illness source attribution is foundational to a risk-based food safety system. We describe a method for attributing US foodborne illnesses caused by nontyphoidal Salmonella enterica, Escherichia coli O157, Listeria monocytogenes, and Campylobacter to 17 food categories using statistical modeling of outbreak data. This method adjusts for epidemiologic factors associated with outbreak size, down-weights older outbreaks, and estimates credibility intervals. On the basis of 952 reported outbreaks and 32,802 illnesses during 1998-2012, we attribute 77% of foodborne Salmonella illnesses to 7 food categories (seeded vegetables, eggs, chicken, other produce, pork, beef, and fruits), 82% of E. coli O157 illnesses to beef and vegetable row crops, 81% of L. monocytogenes illnesses to fruits and dairy, and 74% of Campylobacter illnesses to dairy and chicken. However, because Campylobacter outbreaks probably overrepresent dairy as a source of nonoutbreak campylobacteriosis, we caution against using these Campylobacter attribution estimates without further adjustment.

Chronic Gastrointestinal and Joint-Related Sequelae Associated with Common Foodborne Illnesses: A Scoping Review.

To strengthen the burden estimates for chronic sequelae of foodborne illness, we conducted a scoping review of the current literature for common foodborne pathogens and their associated sequelae. We aim to describe the current literature and gaps in knowledge of chronic sequelae associated with common foodborne illnesses. A comprehensive search was conducted in PubMed, EMBASE, and Web of Science for peer-reviewed articles published January 1, 2000 to April 1, 2018. Articles available in English, of any epidemiological study design, for 10 common foodborne pathogens (Campylobacter, Salmonella, Escherichia coli, Listeria, Shigella, Cryptosporidium, Cyclospora, Giardia, Yersinia, and norovirus) and their associated gastrointestinal (GI)- and joint-related sequelae were included. Of the 6348 titles screened for inclusion, 380 articles underwent full-text review; of those 380, 129 were included for data extraction. Of the bacterial pathogens included in the search terms, the most commonly reported were Salmonella (n = 104) and Campylobacter (n = 99); E. coli (n = 55), Shigella (n = 49), Yersinia (n = 49), and Listeria (n = 15) all had fewer results. Norovirus was the only virus included in our search, with 28 article that reported mostly GI-related sequelae and reactive arthritis (ReA) reported once. For parasitic diseases, Giardia (n = 26) and Cryptosporidium (n = 18) had the most articles, and no results were found for Cyclospora. The most commonly reported GI outcomes were irritable bowel syndrome (IBS; n = 119) and inflammatory bowel disease (n = 29), and ReA (n = 122) or "joint pain" (n = 19) for joint-related sequelae. Salmonella and Campylobacter were most often associated with a variety of outcomes, with ReA (n = 34 and n = 27) and IBS (n = 17 and n = 20) reported most often. This scoping review shows there are still a relatively small number of studies being conducted to understand specific pathogen/outcome relationships. It also shows where important gaps in the impact of chronic sequelae from common foodborne illnesses still exist and where more focused research would best be implemented.

Integrated approaches for the public health prioritization of foodborne and zoonotic pathogens.

To address the persistent problems of foodborne and zoonotic disease, public health officials worldwide face difficult choices about how to best allocate limited resources and target interventions to reduce morbidity and mortality. Data-driven approaches to informing these decisions have been developed in a number of countries. Integrated comparative frameworks generally share three methodological components: estimating incidence of acute illnesses, chronic sequelae, and mortality; attributing pathogen-specific illnesses to foods; and calculating integrated measures of disease burden such as cost of illness, willingness to pay, and health-adjusted life years (HALYs). To discuss the similarities and differences in these approaches, to seek consensus on principles, and to improve international collaboration, the E.U. MED-VET-NET and the U.S.-based Food Safety Research Consortium organized an international conference convened in Berlin, Germany, on July 19-21, 2006. This article draws in part on the deliberations of the conference and discusses general principles, data needs, methodological issues and challenges, and future research needs pertinent to objective data-driven analyses and their potential use for priority setting of foodborne and zoonotic pathogens in public health policy.

Long-term consequences of foodborne infections.

Foodborne infections with Campylobacter, E. coli O157:H7, Listeria monocytogenes, Salmonella, Shigella, Toxoplasma gondii, and other pathogens can result in long-term sequelae to numerous organ systems. These include irritable bowel syndrome, inflammatory bowel disease, reactive arthritis, hemolytic uremic syndrome, chronic kidney disease, Guillain-Barré Syndrome, neurological disorders from acquired and congenital listeriosis and toxoplasmosis, and cognitive and developmental deficits due to diarrheal malnutrition or severe acute illness. A full understanding of the long-term sequelae of foodborne infection is important both for individual patient management by clinicians, as well as to inform food safety and public health decision making.

Ranking the disease burden of 14 pathogens in food sources in the United States using attribution data from outbreak investigations and expert elicitation.

Understanding the relative public health impact of major microbiological hazards across the food supply is critical for a risk-based national food safety system. This study was conducted to estimate the U.S. health burden of 14 major pathogens in 12 broad categories of food and to then rank the resulting 168 pathogen-food combinations. These pathogens examined were Campylobacter, Clostridium perfringens, Escherichia coli O157:H7, Listeria monocytogenes, norovirus, Salmonella enterica, Toxoplasma gondii, and all other FoodNet pathogens. The health burden associated with each pathogen was measured using new estimates of the cost of illness and loss of quality-adjusted life years (QALYs) from acute and chronic illness and mortality. A new method for attributing illness to foods was developed that relies on both outbreak data and expert elicitation. This method assumes that empirical data are generally preferable to expert judgment; thus, outbreak data were used for attribution except where evidence suggests that these data are considered not representative of food attribution. Based on evaluation of outbreak data, expert elicitation, and published scientific literature, outbreak-based attribution estimates for Campylobacter, Toxoplasma, Cryptosporidium, and Yersinia were determined not representative; therefore, expert-based attribution were included for these four pathogens. Sensitivity analyses were conducted to assess the effect of attribution data assumptions on rankings. Disease burden was concentrated among a relatively small number of pathogen-food combinations. The top 10 pairs were responsible for losses of over $8 billion and 36,000 QALYs, or more than 50 % of the total across all pairs. Across all 14 pathogens, poultry, pork, produce, and complex foods were responsible for nearly 60 % of the total cost of illness and loss of QALYs.

Annual cost of illness and quality-adjusted life year losses in the United States due to 14 foodborne pathogens.

In this article we estimate the annual cost of illness and quality-adjusted life year (QALY) loss in the United States caused by 14 of the 31 major foodborne pathogens reported on by Scallan et al. (Emerg. Infect. Dis. 17:7-15, 2011), based on their incidence estimates of foodborne illness in the United States. These 14 pathogens account for 95 % of illnesses and hospitalizations and 98 % of deaths due to identifiable pathogens estimated by Scallan et al. We estimate that these 14 pathogens cause $14.0 billion (ranging from $4.4 billion to $33.0 billion) in cost of illness and a loss of 61,000 QALYs (ranging from 19,000 to 145,000 QALYs) per year. Roughly 90 % of this loss is caused by five pathogens: nontyphoidal Salmonella enterica ($3.3 billion; 17,000 QALYs), Campylobacter spp. ($1.7 billion; 13,300 QALYs), Listeria monocytogenes ($2.6 billion; 9,400 QALYs), Toxoplasma gondii ($3 billion; 11,000 QALYs), and norovirus ($2 billion; 5,000 QALYs). A companion article attributes losses estimated in this study to the consumption of specific categories of foods. To arrive at these estimates, for each pathogen we create disease outcome trees that characterize the symptoms, severities, durations, outcomes, and likelihoods of health states associated with that pathogen. We then estimate the cost of illness (medical costs, productivity loss, and valuation of premature mortality) for each pathogen. We also estimate QALY loss for each health state associated with a given pathogen, using the EuroQol 5D scale. Construction of disease outcome trees, outcome-specific cost of illness, and EuroQol 5D scoring are described in greater detail in a second companion article.

Attributing illness to food.

Identification and prioritization of effective food safety interventions require an understanding of the relationship between food and pathogen from farm to consumption. Critical to this cause is food attribution, the capacity to attribute cases of foodborne disease to the food vehicle or other source responsible for illness. A wide variety of food attribution approaches and data are used around the world, including the analysis of outbreak data, case-control studies, microbial subtyping and source tracking methods, and expert judgment, among others. The Food Safety Research Consortium sponsored the Food Attribution Data Workshop in October 2003 to discuss the virtues and limitations of these approaches and to identify future options for collecting food attribution data in the United States. We summarize workshop discussions and identify challenges that affect progress in this critical component of a risk-based approach to improving food safety.