Sick City: A Literature Review of Global Studies Surveying Circulating Zoonotic Pathogens Across Urban-Rural Gradients

Abstract

An emerging field in epidemiology is to study the impacts of urbanization on disease transmission of zoonotic agents, pathogens that can be communicated from other animals to humans. To study this, a qualitative review of 31 studies conducted across an urban-rural gradient that investigated pathogen survey were reviewed and consolidated to observe trends in pathogen expression respective to the scale of urbanized features. Four categories of pathogens were identified: animal parasites (helminths, cestodes, etc.), bacteria, protists, and viruses. Three categories of demographic were identified: urban, rural, and an urban-rural gradient. In all four pathogen types, more total numbers of distinct pathogens were identified in urban studies overall. Simultaneously, the majority of pathogens discovered in urban studies were identified across multiple urban studies, showing replicability. The literature indicates that urban environments are at a significantly higher risk for zoonotic pathogen transmission. Of the 106 pathogens identified in this study, 36 were relevant to prominent human diseases, of which the majority were found chiefly in urban or urban-rural studies, indicating the central risk of urbanization to pathogen exposure.