Plague Domain

Sometimes healing takes a different, more experimental form than divinity. The Plague domain is derived from necessity more than faith, and was formed during the Plague of Zuggtmoy (also known as the rain of ten thousand spores). Clerics devoted to the plague are easily distinguishable by their oilcloth coats and bird-like masks. If you chose this domain, you may add these two items to your starting equipment. 

Bonus Proficiency

When you choose this domain at 1st level, you gain proficiency with constitution saves.

Rotting Garb

Also starting at 1st level, when you are attacked by a melee range creature, you can use your reaction to force your contagion on them. They must make a Constitution saving throw (DC equal to 8 + your proficiency bonus + your Dexterity modifier) or take 1d4 poison damage for the next 3 rounds. You can use this ability a number of times equal to your Wisdom Modifier after each long rest.

Channel Divinity: Invoke Illness

Starting at 2nd level, you can use your Channel Divinity to force illness upon your enemies.

Chose an enemy within melee range. This creature must succeed a Constitution saving throw (DC equal to 8 + your proficiency bonus + your Wisdom modifier), or they develop an illness based on their roll.

If they fail the save by less than 3, they take 2d8 poison damage.

If they roll 4 points below your save, they also gain a level of exhaustion.

If they roll 8 points below your save they are also blinded for 1d4+1 rounds.

If they roll 12 below your save they are also paralyzed for 1d6+1 rounds.

Leech Therapy

Beginning at 6th level, you gain the ability to summon a small amount of leeches (or frogs) that pool in your hand.

You can make a ranged (15ft) attack action against an ally or enemy to throw the pests.

On an enemy the leeches will latch and frogs poison, dealing 1d4+(Your proficiency bonus) damage for 1d4 rounds.

On ally cast will heal in the same manner.

Contagion Strike

At 8th level, you gain the ability to infuse your weapon strikes with rotten disease. Once per turn, you can summon the plague to a melee weapon to deal an additional 1d8 poison damage. When you reach 14th level, the extra damage increases to 2d8.

Doctor's Orders

Starting at 17th level, your mask always provides fresh air. In addition, you can never contract an illness and have advantage on Constitution saving throws.