There's also another factor to consider in interspecies infections.
Over-fitting.
A virus "trained" on multiple species is targeting biology that is ubiquitous in higher life. The wider range of species a disease can infect, the less likely an individual member of a species is to have genetic variation that leaves it not susceptible to the disease, and the worse an outbreak is likely to be.
Over-fitting.
A virus "trained" on multiple species is targeting biology that is ubiquitous in higher life. The wider range of species a disease can infect, the less likely an individual member of a species is to have genetic variation that leaves it not susceptible to the disease, and the worse an outbreak is likely to be.