How Scientifically Plausible Is the ‘Simian Flu’ in Planet of the Apes?

The Planet of the Apes prequels did much to explain how humans lost their status as the dominant species on the planet—a cataclysmic set of events fueled by a global pandemic known as the “Simian Flu.” This virus, the product of a medical experiment gone horribly wrong, wiped out the vast majority of humans, but it…