Last night, doing Genkai 2, killing the three NMs in Xarcabard, I was diseased by the undead hound type NM (I forget the exact name, not really important to this) As 55THF/WAR, I didn't resist getting diseased, but later as we were walking to the next NM, the 73 WHM/SMN I was with used divine seal Viruna to clear us all of it, but my virus had worn off a minute or two before the WHM stopped us to Viruna. I'm not sure about the 75 war or 75 nin that were with me, as I have filters on, but I think their virus had worn off to (or they could have fully resisted I'm not sure).
I'm just posting this to mention that the 'Resist Virus' Trait reduced the ammount of time I stayed diseased from the attack, even though I didn't resist being diseased in the first place. I hadn't ever seen or heard that happen before so I thought I'd mention it.