Converted this guy a while back. I initially was going to use him as my counts as Typhus, which would still work I suppose. He was painted like the rest of the Death Guard Marines, just with a helluva lot more washes on him. I used the aptly named Typhus Corruption on the sickle and skaven globadier backpack too (thanks to Tom for the idea).
One thing I tried this time was actually finishing the base. I was holding off doing them all until I had a bigger chunk of the army done, so there would be some consistency. It was pretty basic to do though, and I wrote all of it down for next time. I used Army Painter Battle Highland Tuft tufts for the dead looking grass which is a cinch to add and gives the base some life (or death in this case). I'm going with the yellowish color for them as it adds in a little color but still retains the sickly look of Nurgle.