My fortress is struck by a syndrome.
In an attempt to reach beautiful marble (i love it how the bottom of a chalk deposit is made of marble) to standardize on a material for new furniture, i reopened the sealed off caverns. There one of my miners was killed by a so aptly named Forgotten Beast. Since my 4 professional military squads were tired of practice and killing the occasional goblin ambush (defenses agains sieges are excellent) i send them in to dispatch the shrimp. I didn't think too much about its dangerous blood (i cannot remember the exact description) and that might be the doom of my fortress.
With only one casualty the military did an excellent job...but then the trouble started. Dwarfs, children and pets are bursting into a mess of blood at random moments. One moment they decide to drop their activities and rest their wounds, the next one they die of blood loss. I already lost 1/4 of my population (among them my baroness) to this. It can happen while sleeping and in any area of the fortress, so it is not like they die on contact, it is only that when the symptoms are showing they die immediately after.
Even before opening the caverns i took measures to prevent exactly that. All the grown-up dwarves are in a squad and uniformed with socks and leather shoes. The dwarves that die seem to be barefoot or with only one feet covered. The stupid baroness refused to join a squad, so she was already walking around naked and got what she deserved for that indecent behavior.
Dwarves are walking through 2/7 or 3/7 water when entering the kitchen, the dining room, the hospital or the sleeping quarters. This water is refreshed regularly but still contains contaminations from the feed of dwarves (the walls of those sewers are really dirty, it seems the water doesn't flush that away).
Among the contaminations there are smears of Tise the Terrors of Spray's forgotten beast blood. I think this is the source of misery.
Now many dwarves are feeling bad about this situation. They consider it a tragedy when one of their friends or family die and sometimes start throwing tantrums or become melancholic. I can see a problem with that since there are no new immigrants coming. Caravans and diplomats still pass by.
I don't feel like abandoning the fortress and reclaiming. Even though there are only 3 of the original 7 alive, they are the ones that own the place, not some 7 random new ones.
I don't know if the bathing makes the situation better or worse. I don't know if the contaminants from the wall can get into the water. I don't know if the blood of death dwarves can be dangerous to others. But the next time i (re)open a cavern, i'll make sure you cannot enter the fortress again without taking a bath.
It would be wonderful if dwarves were smart enough to put on a pair of the socks and shoes that are in great supply and excellent quality present in the fortress. The method with squads is clumsy and doesn't work all the time. And i would expect the dwarves to prefer some covering when wading through the water or over Dense Cave Moss. Does anyone have a better solution?