Che. Fools. Don't you even know what causes disease? It is demons. Always demons. By showing your fear, you are only going to make it worse.
Industrial: Continue building weapons.
New: Start production of guarigione masks. Guarigione masks are painted masks that cover the face, usually made with cloth or thick iron with a kind if filter to breath through. Demons of sickness feed off each other, making the carrier even weaker, inviting his demonic friends. Guarigione masks cover the face of the diseased and the doctors near them (as sickness demons take helping others as a sign of weakness), making them appear strong and healthy. Have the weapons priests wear them, as well as any currently sick and particularly weak men, such as new parents and the elderly.
Internal: Mask-clad Weapons Priests begin to exercise the demons, using subtle magics and arcane herbs. The rest of the group train in over time, this is no time for us to show weakness as a nation.
Diplomatic:
"This wouldn't have happened if you turned to our religion. Sickness spreads through weakness, obviously you haven't been training enough. We suggest you immediately arm and train all of your population, before this disease spreads further."
The diplomat states, hugging his arbalest tight to his body.
I resend Weapons Priests to everyone East of the river, including the nomads if they are still around. This time, the mask-clad priests offer aid, asking to help by building hospitals to help treat the wounded inside the afflicted countries.