If near is no such entity as spontaneous contemporaries, where on earth did VD and other diseases come from?

various mutations, such as a frameshift mutation (shifting of nucleotides), somatic mutation ( lethal), germ cell mutations, inversions, nondisjuctions. Basically newly the body making mistakes.
sicko's having "relations" next to animals.
monkeys and stuff. they've always have disease, it's up to us to catch it from them.
They are out within, they are just mutating and we are finding them surrounded by places we have never be, like cavernous jungles or from animals.
Mutations and such.