Bubonic plague

The bubonic plague (aka: the plague or black death or black plague) is a form of divine curse which causes physical illness and death.

Transmission

Infection occurs when people start having impure thoughts or commit sins. God quickly becomes angry, and decides to punish them. God makes pain and death happen by either pointing towards the earth, or possibly waving his hand. God sometimes makes no hand motions at all and simply looks the general direction of earth. If God is busy going something else, he doesn't motion or look towards earth at all and simply wills it to happen.
God may or may not choose to punish loved ones instead (example: sons, daughters, spouse, relatives, etc) to further impose his stern lesson upon the living. Ironically, many of these individuals were religiously compliant themselves, but God works in mysterious ways.

Symptoms

The distinguishing symptom of God's anger are the appearance of swelling in areas of sin. If the sinner is guilty of impure sexual thoughts, the swelling appears in the groin. If the sinner is guilty of speaking the lords name in vain (or even contemplating it), swelling in the neck appears.
When God finally chooses the time is right, he issues the full force of his wrath upon the sinner. He takes away their mind to make them crazy, makes them unable to consume food, makes blood spill from where they breath, gives them pain, and makes them shun the light of day.

Treatment

The most effective treatments for the plague are a strict regimen of daily prayer in addition to strong devotion to the church doctrine. It also helps to locate and burn witches, as it has been proven that the plague is also the result of witchcraft.