This is what I would say. Grab a complete blood count to ensure the deer's white blood cells aren't elevated, and you may want to do a few blood cultures, not to mention a wound culture on the infected area. I'll relate this to humans, which are also mammals. First, just because you have an infected leg, doesn't mean you're septic (systemic infection). Our bodies have things (antibodies, wbcs, etc) that localize and limit infections. So as long as you didn't see gangreen (even then I wouldn't think all the meat would be bad) setting in to the upper part of the extremity, I'd say the meat is just fine. As far as the "skinny" part. When people get sick, they generally have a poor appetite. Also, when people are in pain they also tend to not eat. I guess their minds are more concentrated on other things. I'd guess this deer was feeling pain and was definitely sick. The only thing that makes me wonder/worry would be the amount of time that it took for the deer to get skinny. How many pounds was he? Was he ribbed out real bad? If he was just rutting hard and not eating he may have lost some weight, but I wouldn't suspect that he'd lose 100 lbs in a couple weeks. Maybe it was a bowshot? Maybe he'd been walking on that leg for awhile (ie since bow season opened). Maybe your gun season was a month ago. Otherwise I'd suspect that he was a little deer to begin with. If you had a problem with CWD in your area I'd destroy the deer without any questions asked. If you haven't had any cases reported, I'd scratch it off the list and say that deer is just fine to eat, might be a bit gamey and tough, but fine to eat none-the-less.
