CWD was initially spread east of the Mississippi by captive deer breeders moving deer from west of the river east of the river. It was then spread form the pen raised deer to the wild deer. Why every deer farm in this country is nit closed down and burned to the ground is a question every hunter in the country should be asking their respective legislators! Then there was the University on CO that was doing research on CWD in Mule deer and captive breeding them, then released all the deer plus the offspring into the wild that really got it going west of the Mississippi.