Humility meets The Abyss? For BBB? Really?
Darksteel Colossus still beats you for 11 even when infected. All abilities are still turned on. Humility this is not.
The Abyss - typically used in creatureless or non-artifact creatureless decks as a one-sided permanent creature killer. This needs a creature in play to be in play, needs you to affect one of your creatures in order for it to affect one of theirs (technically it could be your creature again) and doesn't necessarily kill their creature. This is not the Abyss.
Seeing as you are searching for an older card that spreads disease and can be used to kill opponents 2 or less toughness creatures, I will reveal the powerhouse that this affect resembles..
Are you ready?

How much does that cost? Yep, 3 mana.
(I'd also say that this is similar in many ways to Attrition, Honden of Infinite Rage and Phyrexian Plaguelord (but without the fat and without the really useful multiple use at instant speed and self-sacrifice abilities))
So this card doesn't actually kill the creature it is enchanting (which may or may not be a good thing, I can certainly imagine you casting this on one of your own creatures - but it certainly isn't a creature killing enchantment until you start affecting your own creatures), only has an effect if you give one of your creatures -2/-2 on your turn before you attack, doesn't kill anything with toughness more than 2 unless you want to lose the Illness too (self-sacrifice, a virtue in a Black card) and doesn't do anything at all on the turn you cast it, nor on your opponent's next turn. In addition, you don't get a choice about giving one of your creatures -2/-2, and even worse, if your opponent doesn't have any creatures (or just one but it is the Ill one) then you have a rather unpleasant choice to make about the target creature that gets -2/-2. Playing with disease is a risky thing, at least for your creatures.
Don't get me wrong, I'd love this in Limited (at {b}{b}{1}, it shouldn't be {b}{b}{b} in my opinion, it's not Necro or Pox!) but it is far from the broken earlier versions of the card