As Davin has also pointed out, it's not enough to have simple genetic differences to target a virus or bacteria. They have to be genetic differences that are involved in the sorts of things that viruses and bacteria do to cells and biological functions. And at that level, there are no real differences in races or ancestries.

I stand by my assertion that if such things were possible, they would have evolved naturally, and there would have been hundreds of infectious diseases throughout recorded history that were specific to race or ancestry. Again, as far as I know, there are none at all.

I am not saying it is totally impossible. Maybe someday an advanced nanotechnological weapon could be developed that actually analyzed specific non-biological genomes and if the green light goes on, attack the host, but I'm not going to lose sleep worrying about someone developing a microscopic gene lab in the near future.

Obviously, there are genetic diseases that are specific to race and ancestry. Sickle cell and Tay-Sachs come immediately to mind, and there are many others.