Why do Animals get Sick? Evolutionary Veterinary Medicine: The Benefits of Expanding from a Comparative to an Evolutionary Perspective

Abstract

Veterinary medicine is comparative, but, as in human medicine, the evolutionary origins of disease susceptibility are not fully considered. Thus while there are good descriptive studies, many ‘why’ questions concerning disease remain unanswered, and many are not even asked. Since disease in every animal species except humans falls under the purview of veterinary medicine, this focus on descriptive ‘how/what’ mechanisms combined with breakthroughs in technology has led to a rapidly expanding knowledge base that is impossible for veterinarians and researchers to keep up with and is overwhelming students. Consideration of evolutionary heritage in veterinary basic teaching/research and clinical case work ups provides a much better and more universal basis for understanding disease than that provided by explanations based only on clinical signs, morphology and molecular mechanisms. For example: evolved structural and functional adaptations for movement and to diet often determine disease susceptibilities across species as well as the effectiveness and toxicity of drugs. Similarly, while specific pathogens vary in their molecular mechanisms of infection, they often exploit the same vulnerabilities as to cell type infected and the features of diseases induced across species. Questions of why disease occurs in specific locations can be understood and further investigated through consideration of organ evolution: for example why vascular tumors arise on the right side of the heart in both dogs and people. Diseases induced through environmental mismatches (e.g.: hemochromatosis), toxins (e.g.: cancer) or changes in microbiome (e.g.: allergic/autoimmune diseases) reveal common shared susceptibility and pathology across species. At the molecular level, understanding the evolutionary basis for why there are both species similarities and differences in disease induced by defects in the same conserved gene (e.g.: dystrophin), can inform treatment options. Adding an evolutionary perspective to veterinary medicine provides a context for organizing and interpreting the ever‐increasing amount of data being generated and allows the critical ‘why’ questions, which are unable to be answered through descriptive studies, to be investigated. In addition, the very close connections between human and animal health (One Health) can only be understood in light of evolution.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.