Havent seen any updated properly built setups for this beast of a weapon. Here it is.
[Lesion] has a passive that when you apply a status affect it gains 100% toxin damage and 15% attack speed. That toxin will combine with the cold to make your viral combination.
I use a unranked cold mod to help proc slash as much as possible. As viral has a cap on how many times you can proc it, slash is unlimited.
[Weeping Wounds] should be replaced by [Drifting Contact] if you aren't using the Naramon Focus school or Swift Momentum, or can swap berserker if using the likes of wisp, volt, etc.