Social determinants of health as upstream risk factors for Salmonella and Campylobacter infections in Pennsylvania
Authors:   , Smith Erica E. , Evans Alison A. 
Published: July 2021

Background: Non-typhoidal Salmonella spp. and Campylobacter spp. are major bacterial causes of acute gastroenteritis, typically characterized by diarrhea, abdominal cramps, fever, and nausea/vomiting. These conditions cause an estimated 1,000,000 and 850,000 illnesses annually in the United States, respectively. In Pennsylvania, these are the most commonly reported enteric bacterial infections, with an average of approximately 1,600 Salmonella and 1,800 Campylobacter cases reported annually statewide during 2011-2015. We hypothesize that social determinants of health such as residence in rural areas (rurality) or food deserts, or socioeconomic position (SEP) may be upstream risk factors for bacterial enteric illness, particularly among the vast majority which are non-outbreak associated, "sporadic" cases. These social determinants influence where we live, where we are able to shop and eat, and what foods we buy, which all impact our risk of foodborne or enteric illness, but have not yet been characterized in the United States. The purpose of this study was to evaluate food, water and animal exposures and disease rates by rurality, food desert residence and SEP (measured by race/ethnicity, poverty and educational attainment). Study Population and Methods: The study population included sporadic, domestically acquired non-Typhoidal salmonellosis and campylobacteriosis cases reported in Pennsylvania during 2011-2016. Food, water and animal exposures reported by case-patients during public health investigation and census tract disease rates were compared by rurality (paper 1), food desert residence (paper 2), and race/ethnicity, poverty, and educational attainment (paper 3). Results: Salmonellosis and campylobacteriosis rates were higher in rural census tracts than urban census tracts. Food exposures such as meat, poultry, seafood and eggs were more common among urban cases than rural cases, while exposures such as unpasteurized milk, well water and animal contact were more common among rural cases than urban cases. Rates of both conditions were lower in food deserts. Case-patients residing in food deserts were more likely to report eating restaurant meals and fresh produce, and less likely to report consuming meat, poultry, seafood, eggs or unpasteurized dairy/juice than case-patients residing outside of food deserts. Residents of lower SEP tracts more frequently reported meat, poultry, seafood or eggs, and less frequently reported produce, restaurant meals, well water, recreational water, or animal exposures. Salmonellosis rates were higher and campylobacteriosis rates were lower in lower SEP census tracts. Public Health Implications: Public Health Implications Public health programs to reduce bacterial enteric diseases such as Salmonella and Campylobacter should be tailored for communities. In urban areas, programs should focus on reducing contamination of food sources such as poultry and eggs, and on food safety practices to reduce cross contamination from these sources in restaurant and home kitchens. In rural areas, programs should focus on reducing consumption of unpasteurized milk, on testing and treating well water for pathogens, and on appropriate hygiene after contact with animals. Although evidence suggests a high potential contamination risk of foods sold in small markets, safe food handling in the home or differential under-reporting of disease may be contributing to lower disease rates in food deserts. Access to fresh food is critical to health equity, but these foods may increase foodborne disease risk. Regulatory authorities should work to mitigate foodborne disease risk in food deserts. Programs to increase fresh produce access should consider including food safety education for proprietors and customers. Enteric disease control programs in lower SEP areas should focus on reducing structural barriers to food access and improving microbial food quality. In higher SEP areas, they should focus on mitigating well water and animal exposure.