Frinstance,
if two given human races are mutually interfertile, then
diseases
could (probably) jump back and forth with little issue.
Given that the current pandemic jumped to humans from other species, that the annual flu is a product of viruses mixing in a variety of non-human hosts, that many viral diseases have known or unknown non-human reservoirs (Ebola, for instance
or AIDS which we THINK arose in some other species, and the first jump to humans occurred as far back as 1916 or so) it’s clear viruses commonly cross mammalian species lines, so my initial thought is that any race of mammalian terran origination are vulnerable
to viruses from other terran mammal-derived species.
However, viruses are absolutely tied to terran DNA-based cellular mechanisms; truly alien species are not likely to be susceptible, nor are we going to be susceptible to theirs.
Bacteria and fungal pathogens, however, are enormously looser in their species-specificity; they merely require a hospitable environment to grow, so those could conceivably infect non-terrestrial species; often to catastrophic effect if there
is no immunity or treatment to the pathogen.
This would go the other way, as well, terran derived species would have zero immunity to alien-derived ‘bacterial’ diseases.
--
Bruce Johnson
University of Arizona
College of Pharmacy
Information Technology Group
Institutions do not have opinions, merely customs