There is ONE (and only one) way to prove that you are wrong.

If somebody were to (a) extract the blood of a sick person, (b) isolate the specific virus believed to be the cause, (c) purify that virus so that ONLY that virus were in a test tube, (d) and then test that virus to find out if it makes animals/people sick.

If that were done, then somebody would PROVE that you are wrong. They would also win a nobel prize and be a household name around the world, showered with millions of dollars in grant money.

Funny ... nobody has ever bothered to do it.