SH2D3A and infection: There is much greater virus diversity between equine isolates than is currently described for canine isolates (Pybus & Thézé, 2015), and several studies demonstrate transmission and pathology of infection in the horse (Pfaender et al., 2015; Ramsay et al., 2015; Scheel et al., 2015); these observations are consistent with the horse being the primary host, and for this reason we have used an equine virus (NSP1, KP325401) as the type isolate.