I see logic with those abilities not proccing ZA, as they are passive, but Howling Attack and even Disease Breath should proc it.
Howling attack isn't bad though. I see DoTs and Aura's not procing swarms cause they're so frequent. Howling, not so much.
Same reason Pack Savagery doesn't work on Avatars: the effect requires a target for it to resolve, and the unit can't be selected as a target unless it's coded as a basic attack.