Human viruses: discovery and emergence

Woolhouse, Mark; Scott, Fiona; Hudson, Zoe; Howey, Richard; Chase-Topping, Margo

(c) Drivers of emergence Several reviews [10, 26, 36] have listed so-called 'drivers' of the emergence of novel viruses or other pathogens. These constitute a diverse set of environmental and biological factors, many of which-such as 'urbanization' or 'land use'-seem intuitively reasonable but are too broad to relate to mechanistic causes of emergence. Moreover, identification of drivers is usually a subjective exercise: there are very few formal tests of the idea that a specific driver is associated with the emergence of a specific pathogen or set of pathogens. In many cases, this would be a challenging exercise: many drivers have only indirect effects on emergence (e.g. climate change, which is often linked with changing distributions of disease vectors); and often an emergence event has multiple causes (good examples would be the emergence of Nipah virus or SARS coronavirus).