ABSTRACT
Emerging viruses are classified as those viruses that are new to human hosts, rising significantly in incidence, or have established endemicity in a new geographic location. In contrast, re-emerging viruses are those that were largely controlled and whose incidence is rising again. Emerging viruses that are of primary concern to human health, as of this writing, belong to a relatively small number of viral taxa, and almost exclusively feature RNA genomes. This chapter aims to introduce general principles that drive viral emergence, identify several prominent emerging viruses (Table 50.1) and note their clinical presentations (Table 50.2), recommended treatment and control (Table 50.3), diagnostic approaches and recommendations, competent transmission vectors (Table 50.4), synonyms and diagnostic codes (Table 50.5), and geographic distributions (Figures 50.1–50.13). This chapter will only briefly discuss re-emerging diseases (Table 50.6) and will defer discussions of novel pandemic influenza virus strains and human immunodeficiency virus (HIV) to more specialized resources due to the depth and broad scope of these topics. We have also declined to include additional viruses that are at times included in the category of emerging viruses due to either their current global ubiquity and disease burden following re-emergence (e.g., dengue virus) or the ambiguity surrounding their causal role in disease outbreaks (e.g., Bas-Congo virus, Bornavirus) [1, 2].
