Throat Leeches

Minuscule parasites known as throat leeches inhabit the fresh waterways of Chults swamps and Rivers. Any giant or humanoid that swallows tainted water is exposed to the disease. 
Any exposed creature must succeed on a DC 12 Constitution saving throw or contract the disease, beginning at stage 1. While infected, the creature must repeat the saving throw once every 24 hours. On a successful save, the creature's condition decreases a stage. If they fail the save, the condition progresses a stage. If the creature successfully saves while on stage 1, the disease is shaken off and they are no longer infected.

Type

Parasitic

Stage 1
The infected creature's throat begins to inflame causing soreness and shortness of breath. This gives the creature disadvantage on Strength, Constitution, and Charisma checks.
Stage 2
The pain becomes excruciating and the infected creature is unable to sleep deeply. The creature suffers 2 (1d4) necrotic damage every hour and can't benefit from healing or exhaustion recovery during a long rest. 
Stage 3
The infected creature loses the ability to speak and the pain becomes even worse as the leeches continue to drain vitality from their host. The damage inflicted hourly increases to 3 (1d6) necrotic damage.