[PvK]

Well I know a little.

Fever Fetish worn = 100% chance of diseased affliction. (not that you asked)

Burden of Time = small chance for everyone in the world to gain an affliction, or just drop dead. I don't think disease is any more likely than other afflictions.

Starvation seems to work by taking the need for supplies, subtracting supplies available, and then sprinkling that many "starving" effects randomly on the troops who need food (not leaders). If a unit gets a "starving" hit who is already starving, he gets diseased. Survival skill protects to some degree in the correct terrain type, but I'm not sure exactly how that works.

Sites that disease... I assume have a random chance of diseasing anyone in the province, every turn. Same with miasma dominion. Leaders can get diseased this way.

Note that a regeneration item can forestall death from disease, but the victim will eventually become an afflicted wreck.

I haven't met the Harvester of Sorrows, but my guess is he would work like a site that diseases.

Same deal for Bane Venom charm and disease, although the wearer is I think diseased immediately, and I expect it also causes population loss and unrest.

PvK