Figure 2.

All currently recognized human-infective RNA viruses categorized with respect to their ability to infect and transmit from humans (levels 2, 3, and 4 of the virus pyramid—see Fig. 1) and distinguished in terms of transmission route (green for vector-borne transmission, blue for other routes) and nature of diagnostic evidence (the viruses not in boldface type have only been reported in humans using serology-based methods). doi:10.1128/microbiolspec.OH-0001-2012.f2