Curse Plague

You throw a flaming wine bottle of oil at your target, which disappears before impact without causing harm when the spell is cast.  The target must make a Wisdom save vs. the caster's spell save DC or be affected by the curse plague.  The curse plague affects any humanoid who is not immune to disease.  Persons immune to charm or charm effects cannot be affected by the curse plague.

On a failed save, the person becomes afflicted with the curse.  For the next 5 days, whenever an afflicted is within 10 feet of an open flame, the curse plague spreads to all persons within 10 feet of him who must then make a Wisdom save or become afflicted themselves.  Thereafter, they can spread the curse plague in the same manner. The affliction lasts a total of 5-days but can rapidly spread through a population.

For the duration, an afflicted gains a level of exhaustion.  Each day at dawn, an afflicted must make a Constitution save vs. the spell caster's DC.  Any day he fails this save, he gains one additional level of exhaustion.  Whenever an afflicted would otherwise gain a level of exhaustion on a failed save of any kind, he/she makes that save with Disadvantage.  Neither a short or long rest removes any levels of exhaustion from the afflicted.

Another Wisdom save to overcome the curse plague is permitted to an afflicted at the end of any turn where he has been reduced to 1/2 of his total hit points by injury (excluding the impact of level 4 of exhaustion.)  A lesser restoration or similar magic will remove the affliction from one person.  The curse plague can be dispelled on one afflicted by a successful dispel magic cast on him.  A remove curse cast upon an afflicted will also end the effect of the curse plague on the recipient.  A person confined in a magic circle cannot become afflicted with the curse plague while within the protective radius of that spell and if he is already afflicted, does not spread the curse plague.  A person within a paladin's Aura of Devotion has a similar protection.

Patient Zero Effect:  Casting a successful dispel magic on the original target of the spell during the curse plague's duration will completely remove the curse plague from anyone afflicted by it.

At Higher Levels. When you cast this spell using an 8th-level spell slot, the duration is 10 days. When you use an 9th-level spell slot, the duration is 30 days.