How do deer get CWD?
CWD spreads deer-to-deer through saliva, urine, feces, and direct contact, plus environmentally through prion-contaminated soil and plants. Once introduced to an area, prions persist in soil for years and can infect deer that come through later. Captive deer operations and natural high-density congregation points (mineral licks, food plots, scrapes) accelerate transmission.
Prions are misfolded proteins, not viruses or bacteria. They don't degrade with normal environmental cycles, can't be killed by typical disinfectants, and accumulate in soil. Once a property has CWD, the prion load only increases over time.
This is why state wildlife agencies impose carcass-transport restrictions, ban supplemental feeding in CWD zones, and conduct culling programs. See your state's disease risk pages for current zones and regulations.