1) Untreated wood has been used for knife handles for thousands of years.
(Examples of thousand year old plus fixed blade knives with untreated wood handles can be seen at major museums.)
Untreated wood handles on pocket knives have been used for hundreds of years, and last just fine.
Folding knives dating to pre-1776 have been found on Revolutionary Battlefields. The wood is in better condition than the blade ... even after being buried in the dirt for 200 or more years.
Infusing a wood with an epoxy is effectively making the wood a plastic.
From my experience in using a "treated" wood knife handle compared to an untreated handle of the same wood, the treated wood does not give as good of grip.
Concerning the "nasties"; germs, bacteria, etcetera:
Do you really think it is even possible to keep your knives, plates, glasses/cups, forks, spoons, hands, pots, pans, etcetera, etcetera sterile?
(It ain't possible. Exposure to air contaminates them.)
If you want a wood, bone, horn, antler, or leather handle hunting knife, don't over think it. Just get one that you like. Wood has been used for thousands of years, just like bone, horn, leather, and other natural materials, yet the "humans" still managed to flourish - even in the days when a blade was simply wiped off with a leaf, dirty loincloth, or the fur of whatever critter was just made ready for cooking ... or eating raw ....