Interesting article I read a while back that talks about how human evolution was due in part to our gut bacteria with whim we share a symbiotic relationship and that the bacteria evolved with us. Not saying it's definitive but it makes sense when you think of it. So if there is intelligent design it's happening as you digest that donut.
I had a professor that suggested polio could have played a serious role in the development of our species. He showed the partial paralyzingly of chimpanzees forced them to "walk upright". There is also an awesome science fiction book called "Darwin's Radio". Great read. It talks about viruses and phages having a direct link to genetic mutation and symbiotic adaptation.
I trust the intelligent design part was tongue in cheek. I also read about this recently. I think it's fascinating.
I heard something about that in passing. Joe Rogan was actually talking about it on his podcast.
An interesting article. Incidentally, I never fart, I ventilate gas and so does everyone else because gas is a by product of the enzymatic process of digestion. Of course, there are those who will claim that they do neither, they must be hermetically sealed.