Extract from an General Instructional, published in Itis-Mae, dating to approximately Ar850
The Benevolence of the Pantheon, and their gifts of Right Cleanliness and Healing Arts, have risen Mortality from the diseased squalor of the pre-theistic darkness.
Nonetheless, pestilence and plague still afflicts this world. Spirits of corruption work against Mortality and the Deities that protect us. Learned Theologians teach us of the following progression of stages in the spread of a pestilence.
FIRST, the bearers of corruption will arrive. Be they Mortality, or beast, for all sickness is borne by living flesh.
SECOND, this will spread among the population. Those practicing Healing Arts will be at gravest risk.
THIRD, the priesthood and healers of the city will be struck down. Those intercedents between Divinity and Mortality, protectors of health, must be killed for the corruption to take hold. Be this achieved by ill timing, or cultists of corruption assaulting their persons, or the effects of the sickness itself; this is a grave step in the progress of a plague.
FOURTH, the illness will begin to spread unchecked. Panic will disrupt the daily order, and Right Cleanliness is forgotten, increasing the corruption.
FIFTH, many will die and many will flee. Those fleeing will bear the illness in their flesh to fresh lands, where the corruption may take a new root.