Aside from Undead Priests and their Devouring Plague, there are no player abilities that inflict the disease Dispel Type. So far, two disease-based abilities have been revealed: Blade Strike and Blood Strike. Designed to work off each other, Blade Strike is an attack that applies a disease on the target in addition to base damage while Blood Strike deals damage based on the number of diseases on the target. Death Knights are also able to raise Ghouls to fight for them and are projected to have an ability that applies a disease on their targets. Load up on Airborne, because it's going to get pretty toxic in Northrend.