Bio-warfare In Middle-earth

[Zigûr]

Originally Posted by Inziladun

If the Orcs were 'corrupted' Elves, they should have at least some measure of an Elf's innate disease immunity. Even if that resistance was diluted, perhaps it provided enough protection that Morgoth (and Sauron) weren't overly concerned about casualties in their own forces.

Given the corruption of the Orcish hröa I would say that it's possible they lost the Elvish immunity to disease in the same way that they lost their longevity and the like, "the fëa dragging down the hröa in its descent into Morgothism." (Morgoth's Ring) Professor Tolkien mentions this in the context of the properties of Elvish fëa and hröa, and how corruption of the former corrupted the latter, so I would say this is a possibility.

I think it's altogether likely that Sauron, if he did instigate the plague, damaged his own people as well, but expected in the subsequent generations that they would replenish themselves more than sufficiently, which they did. I don't expect that Orcs and the like were immune any more than the Easterlings surely weren't.