I’ve been reading about how, as the hunter/gatherer of our pre-historic past transformed through domestication of plants and animals into sedentary farmer, became an unwilling host for viruses carried by animals. The enterprising virus found fertile ground to breed and grow and very little resistance to his (or her, who can tell with viruses) incursions into the human blood stream.
The results of this viral attack were massive die-offs of all but a small percentage of people who were fortunate enough to have a natural or cultivated resistance. These survivors passed their genetic wherewithal to their progeny and from there on to future generations, who would over time encounter new and exotic viruses they had never before encountered that would attack the unsuspecting and appetizing innocents and the cycle would begin again.
Civilizations evolved, became more complex and medical science made amazing advances. Hubris and inattention led to the belief we had won the battle with invasive viral infection.
I guess we have to chalk one up for the viruses.