Date of Award
2024
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Animal Biosciences
First Advisor
Andrea Etter
Second Advisor
Rebecca Guy
Abstract
Campylobacter spp. and Salmonella enterica are two zoonotic pathogens estimated to cause over 800,000 and one million illnesses annually in the United States, respectively. These causative agents for bacterial foodborne illness are burdensome to human health, productivity, and the economy. Furthermore, specific serovars of Salmonella are more commonly implicated in outbreaks and adverse health outcomes including hospitalization, blood infections, and death. Both Campylobacter spp. and Salmonella enterica are commonly associated with poultry, though infection is largely asymptomatic in birds. Infections among humans resulting from contact with live poultry are commonly seen worldwide as well as in Vermont specifically. Concurrently, small scale poultry operations with birds kept for self-consumption purposes or as pets (“backyard poultry”), are becoming more popular in the U.S. The evaluation of prevalence and characteristics of these bacteria among backyard poultry is understudied. The objectives of this research were to (1) determine prevalence of Salmonella enterica and Campylobacter spp. among VT backyard poultry in 2022-2023; (2) identify risk factors associated with poultry infection; and (3) characterize genomes and clinical relevance of Salmonella isolates. Seventy backyard poultry holdings, or “farms” were sampled in 2022-2024, and farm characteristics were documented. Microbiological and molecular methods were used to test for the presence of Campylobacter spp. and Salmonella enterica in soiled poultry bedding; prevalence was characterized among farms across the state, farm characteristics were tested via Fisher’s Exact tests and logistic regression to evaluate potential risk factors associated with bacterial carriage, and whole genome sequencing was performed to analyze Salmonella enterica isolates for serovar distribution, frequency of antimicrobial resistance genes, and implication in human illnesses. Overall, Campylobacter spp. and Salmonella enterica were detected among 19.05% and 12.86% of backyard poultry farms, respectively. A wide variety of species of birds, ages of birds, housing styles, etc. were observed, and risk factors associated with bacterial carriage were determined. Six different Salmonella serovars and seven different antimicrobial resistance genes were detected. Data show high levels of genetic similarity between Salmonella isolates from poultry, and clinical isolates. Both bacteria pose a substantial public health risk to backyard poultry owners and caretakers, and enhanced biosecurity should be encouraged to prevent potential illness.
Language
en
Number of Pages
135 p.
Recommended Citation
Patch, Chelsey, "Characterizing Prevalence, Genomics, and Risk Factors of Campylobacter spp. snd Salmonella enterica Isolated Among Backyard Poultry in Vermont" (2024). Graduate College Dissertations and Theses. 1964.
https://scholarworks.uvm.edu/graddis/1964