It could happen and since China is the USA’s main enemy, maybe the US did it, and this might only be the start. Well, why not get rid of the troublesome Middle East and next, Sub-Saharan Africa (Africa expected to grow at a huge rate in the next century), though they’re not really doing anything to anyone? The last one is the most cruel.
But the problem with bio-weapons is they could come home to hurt the people releasing them! I mean, the whites were only able to use bio-weapons effectively against the Native Americans cause they, the whites, had immunity. Of course, that whole thing wasn’t done purposely – it just happened.