I chose a source you cited as credible. The original study is by Lansteiner & Popper, published in 1909. That's very old and it's in German, so here's another scientific article describing it. Milestones in Early Poliomyelitis Research (1840 to 1949) - PMC share.google/jRHahIqUiSoR...
Lol, my favorite "proof" is when they injected dying genetic material into the spinal chords and brains of monkeys to prove paralysis This is literally pseudoscience at its finest. Didn't expose the monkeys to polio in natural ways. Dumbed dying tissue into their spinal chords Science bitch!