S. A. Headley is an internationally recognized health scientist in veterinary pathology and preventive medicine whose work bridges animal health, infectious disease biology, and population-level health protection. His research expertise spans veterinary pathology, molecular diagnostics, neuropathology, respiratory and reproductive diseases, and emerging and zoonotic infections affecting livestock, with particular emphasis on viral and bacterial pathogens of major agricultural and public health relevance. He has produced an extensive and highly cited body of peer-reviewed research published in leading international journals and has collaborated widely with academic institutions, diagnostic laboratories, and research networks across multiple countries. His work has strengthened disease surveillance, improved differential diagnosis, and informed evidence-based control strategies in food-producing animals. Through sustained academic leadership, mentorship, and policy-relevant research, his contributions support animal welfare, agricultural sustainability, and broader One Health goals with clear societal and economic impact. He has 2551 citations from 193 documents with an h-index of 26.