Two biggies:

1.) Disease transmission cycle: EHD can kill a lot of animals all at once but the herd recovers because the disease tramsission cycle is ‘broken’ when the midges that transmit the disease die off during the winter and by animals getting the virus and surviving thereby getting some immunity. It tends to kill in 5/10 year cycles. CWD on the other hand hasn’t really been shown to have a break in the disease transmission cycle. Animals get it, make more animals sick, and the prevalence rates are just worse and worse and worse. With EHD things get better in a couple years, with CWD it doesn’t. EHD is like a fever where for a few days everything sucks but you’re better. CWD is a slow cancer and it doesn’t look like there is going to be a cure. It will slowly get worse and worse and worse in areas that have the disease. Some areas of Wisconsin where the disease has been present since early 2000s have progressed from low prevalence rates to 40-50 percent prevalence rates in 2 1/2 year old or older bucks. In these areas very few bucks are going to be reaching their 4th birthday. They studied one mule deer herd in Wyoming and it is projected to go extinct in the next few decades. CWD is a downward spiral with no end in sight sort of thing.EHD is a rose in comparison.

2.) human health concerns - prion diseases have shown a remarkable ability to jump between mammal species due the similarity between our protein structures. Birds, fish and reptiles can’t get them, but between mammals, all bets are off. It’s really a free for all. They can also even go through one species to kill another. In one experiment they Fed or injected mice with cwd but they didn’t die. They fed those mice to ferrets and the ferrets died. They fed the ferrets to the original mice species and it killed them when it didn’t before. Crazy stuff.