An Interdisciplinary Framework for Assessing One Health Dimensions of Environmental Contamination in Livestock-Human Interface Communities in Kano State, North West Nigeria

The One Health paradigm, recognizing the interdependence of human, animal, and ecosystem health, offers a theoretically rich but methodologically underspecified framework for analyzing environmental contamination in agricultural settings where people, livestock, and shared environments are intimately coupled. This dissertation develops and applies an interdisciplinary One Health assessment framework to examine environmental contamination and its human-animal-ecosystem health implications in livestock-intensive communities in Kano State, North West Nigeria. The framework integrates environmental toxicology, veterinary epidemiology, human environmental health epidemiology, and ecosystem ecology within a social-ecological systems design. Three communities with varying livestock densities were studied over twenty-four months. Environmental samples of water, soil, feed, and air were analyzed for heavy metals, zoonotic bacterial pathogens (Brucella, Salmonella, Campylobacter), antibiotic residues, and antimicrobial resistance genes. Human health surveys assessed zoonotic disease exposure, antibiotic use behaviors, and environmental health outcomes. Veterinary records and livestock health assessments captured animal health dimensions. Simultaneous measurement allowed construction of shared exposure matrices and cross-species outcome comparisons. Results demonstrated convergent antimicrobial resistance gene profiles in human stool, livestock feces, water sources, and soil, suggesting a shared environmental resistance reservoir. Antibiotic residue concentrations in surface water exceeded ecotoxicological thresholds in seventy-one percent of sites. Human zoonotic seroprevalence was significantly elevated in communities with higher livestock densities. The dissertation makes an original contribution by operationalizing One Health assessment methodology in a Nigerian livestock-agricultural context. Keywords: One Health, environmental contamination, antimicrobial resistance, Kano State, livestock communities.