Locust, Fleas and Rats - It's been done, and to sometimes devastating effect. The Black Plague is theorized by some to be the result of a lingering bio-terror attack from Asia. Today, using hordes or plagues of animals carrying disease in war would be completely illegal.
And that's where you're wrong!
A dead soldier is left there for later pick up.
A wounded soldier imediatly takes 1-2 of his buddies to carry him to safety, wham 3 soldiers less with one bullet.
Remember: There are many kinds of wounded but only one kind of dead.
#16
Toxin, think greek for bow.
They lased their arrows with poop and decaying bodies way back then, nothing new.