Contagion
Your touch inflicts a magical contagion. The target must succeed on a Constitution saving throw or take 11d8 Necrotic damage and have the Poisoned condition. Also, choose one ability when you cast the spell. While Poisoned, the target has Disadvantage on saving throws made with the chosen ability. The target must repeat the saving throw at the end of each of its turns until it gets three successes or failures. If the target succeeds on three of these saves, the spell ends on the target. If the target fails three of the saves, the spell lasts for 7 days on it. Whenever the Poisoned target receives an effect that would end the Poisoned condition, the target must succeed on a Constitution saving throw, or the Poisoned condition doesn't end on it.
Contagion 5e 2024 vs. 2014 edition differences
The 2024 version inflicts 11d8 necrotic damage and imposes the Poisoned condition with disadvantage on one ability, while the 2014 version poisons the target and applies a disease after three failed saves. The 2024 version requires repeated saves to end the spell, with additional damage and ability disadvantage mechanics.