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.

Interesting. If corrupted Elves (ie the neo theory that they weren't might have bearing on this item).

We didn't learn much about their lifespan etc and native resilience, except that they bore young in the same manner as Elves and Men. I've been wanting to look at the Black Silmarillion to see if there was anything interesting in it about stuff like that.

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.

As is my wont, I sometimes see great events of the 'real' world through the lens of Tolkien.

The current Great Plague of our time reminded me of this thread, and I thought I'd bump it to see if there were any fresh ideas.

Without the Germ Theory, I still wonder how the illness infections, and even more, the spread, were accomplished.

Orcs ate pangolins, thus creating the Orcoronavirus.

Ouch...

I'm here 'til Tuesday; try the veal! :D

Aaaand meat's back on the menu, boys! We won't tell you whose. :p

Having reread the thread, I am actually surprised that I still agree entirely with my post 4 years ago.

But here's a new thought: if Orcs ate rubbish meat and even other orcs, and Gollum ate Orcs and occasional other animals, it's a wonder he didn't get sick more often. Infectious diseases which accumulate in the animal reservoir can peak in the apex predators, because they eat other animals (which might also have eaten other animals in turn) and are thus more likely to eat something infected. Proportionally, assuming the infection can be carried by all the animals involved, you're more likely to come across it in a predator than in his prey. For instance, sleeping sickness has a reservoir in domestic animals, but in the wild its biggest reservoir is lions. So either the Ring was keeping Gollum healthy, or he was a gourmand eater when it came to orc meat, or he actually did get sick from various things, including your basic food poisoning, and we just don't know about it. As for Orcs... probably had very tough stomachs, and also probably didn't keep around anyone to sick to work.

Long before Pasteur, people had observed that contact with or proximity to infected people, or objects associated with them, led to contagion. Quarantine was used a thousand years before germ theory! (Farther back than that, WRT leprosy). See also the practice of catapulting the corpses of disease victims into a besieged city, and the infamous if distorted tale of Lord Amherst and his smallpox blankets. (Distorted because it didn't and couldn't work; the smallpox virus can't be transferred that way).

With the plagues sent by Morgoth and Sauron though, there doesn't seem to be any physical medium for the sickness to be transferred to their enemies. The illness came "on the wind".
Contagion as we see it requires an index case for transmission.

The characterization that the plague was carried "on the wind" is a typical archaic reference. The recognition of means of transmission is a modern discovery. I have seen the Spanish Flu from 1918 characterized in period pieces as black clouds and smog. Tolkien would not attempt to incorporate concepts such as aerosol transmission into his mythos; they would be out of place.

Well, he was certainly familiar with both the 1918 Influenza and the gas warfare on the Great War battlefields. I do agree though that Tolkien was rather averse to 'scientific' explanations for fantasy plot elements.

To me the mystery is whether the illness was a physical malady or something spiritual.

If the former, there must have been some means of spreading the affliction to the right people.
If the latter, how would it be communicated from one victim to the next?

I would suggest plague is both a physical and spiritual malady. Here is a description by Giovanni Boccaccio, who lived through and wrote about the Black Death of 1348:

Such an insidious and all-consuming plague loosened all familial ties, and ended all pretense of hope and humanity. It was, for most of those living amongst the dying, the end of the world, literally. Barbara Tuchman in her splendid history "A Distant Mirror: The Calamitous 14th Century" wrote of one such instance:

Having no conception of a plague carried by fleas on the backs of rats, and rats being a constant companion of medieval man -- and therefore not out of the ordinary -- it was, as a Welsh dirge described the plague "death coming in our midst like black smoke". Tuchman condensed several reports of the coming of the plague through Asia and the Middle-East and then to Europe into one concise and fantastic (as in mythological) paragraph:

Therefore, to a pre-technological, superstitious and non-scientific society, a plague coming on a foul wind has historical precedent.

I agree that science and fantasy shouldn't always mix - though there is a part of my brain that pops the question of whether Faramir, Eowyn, and Merry had respiratory acidosis while unconscious from the Black Breath... ^.^

If the malady was spiritual (akin to the Black Breath, the depression-which-kills-directly, or something similar), it would not even need a contagion for transmission. If Sauron poisoned Gondor's population by taking away their will to fight for life as the Nazgul did, would it have required any physical means or vector? I would imagine that version as more of a changing of moods like the changing of weather: something that hovers over everyone at once, with some people perhaps being a bit more affected than others. Like rainfall. Or electromagnetic radiation. Or something else that directly affects the population at large.

If that was so, though, I do wonder whether Gondor's famous healers would have used words like "plague" for something that was not infectious. And how well they would be able to differentiate infectious versus the "curse from above" scenario.

This is again an offshoot of my old vision of the plague as a physical explosion of Sauron's malice in the form of pathetic fallacy. But whether a physical infection or a spiritual malady - I might even prefer the latter, but wouldn't bet against the former.

Malaria means literally "bad air," because it was believed by the ancients to be caused by the noisesome vapors of swamps and marshes.