Netherese Fauna Blight

The jungles of Harnash are replete with poisons and diseases that the doctors and dulceurs have had to heal for millennia. One of the most challenging and deadly diseases to come through the infirmary doors however does not come from the dense jungle environment, but from the great ancient ruin of Gadenthor.
As it took many centuries after the fall of Gadenthor for people to be able to actually gain entry to any of the buildings of the city, the Harnashi explorers were well prepared for the idea that an ancient civilisation of a vastly different people may have had different physiologies, different diets and even different illnesses. Care was taken in delving into these Netherese structures to avoid contact with as much as possible, and many early catastrophes were avoided with due diligence from these trailblazers.
It wasn't until the lowest few streets of the city, closest to the ground, had been cleared and ramps had been built for access, that the most dangerous disease became known. Harnash contains a sizable population of centaurs, and when one got too close to an oddly charred animal pen, the Netherese Fauna Blight became apparent. Later research determined that some meat trader had gotten into a conflict with a devil, who had cursed their livestock with a deadly disease. A centaur being of course different, but just similar enough to a horse, managed to contract the disease that had laid dormant for centuries, kept extant by the devil's curse.
Netherese Fauna Blight is a consumptive disease that attacks stomach first, causing ravenous hunger for a few days before it spreads to the rest of the body. It takes about a week from contracting the blight before the centaur is half-covered in ashy, hard scales and dies from massive organ failure. It's brutal, and swift, and for a long time, completely untreatable. As long as they were isolated from other centaurs quickly, it doesn't easily spread across other species. To this day, few centaurs are keen to venture anywhere near Gadenthor, but still occasionally some artifact poorly transferred back from the ruins causes another breakout. Thankfully medicine has evolved to be able to counter the effects, as long as it is caught swiftly.