You attempt to worsen the diseases within a creature of your choice within range. The target must make a Constitution saving throw for each disease it is suffering from. On a failed save, it immediately fails a saving throw associated with the disease and has disadvantage on the next saving throw caused by the disease. On a successful save, the creature has disadvantage on the next saving throw caused by the disease.   If the creature failed the spell’s save by 5 or more, it immediately fails the saving throw associated with the disease an additional time.