Classification Matters: A One Health Perspective

Abstract

This paper introduces a promising ecological approach to classifying infectious diseases based on the reservoir of the causative organism. According to this approach, all infectious diseases are classified as anthroponoses, zoonoses, and sapronoses. Among these three, zoonoses are the most used and known category, including diseases naturally transmitted between vertebrate animals and humans. The principal reservoir of the pathogen is often populations of certain animal species. The term “anthroponoses” denotes diseases where human hosts are central to the pathogen’s life cycle and provide its survival from an evolutionary perspective. These diseases circulate only among humans, and animals are not susceptible to them. Finally, sapronoses is an emerging concept for categorizing diseases where the causative organisms grow saprophytically in the environment and parasitically in vertebrate hosts, including humans. However, the parasitic phase usually plays a secondary role. Recognizing infectious diseases as sapronoses highlights the role of the connection between diseases among humans, animals, and the environment. This ecological approach to classifying infectious diseases is worth exploring, especially in the context of One Health, which emphasizes the interdependence between these three dimensions. Theoretical exploration focusing on the complex dynamics of pathogen-host interactions is needed to develop this classification further.