and feces. Those prions exist for years on plants and in the soil, where other animals pick them up. For this reason, CWD spreads quickly among captive deer which are in pens.

In the wild, the disease tends to move more slowly across the landscape because wild deer congregate in smaller numbers and have localized ranges unless food shortages, predator pressure or severe weather forces them to travel.

At first, it’s difficult to find CWD in wild herds even when it’s present.

Once a cervid contracts the disease, it is undetectable to the naked eye for almost two years, until the animal is within only a few months of death.

At that point, the symptoms become obvious, including droopy ears and a malnourished appearance. As abnormal prions increase in the brain andPapi serves as mentor to Twins' prospect Vargas

Slugger takes 23-year-old Vargas under wing during Spring Training

By Maureen Mullen / Special to MLB.com

FORT MYERS, Fla. -- David Ortiz knows how difficult it can be for young players coming up through the Minors trying to make their way to the big leagues. After all, Ortiz, who is 38 and entering his 18th season in the Majors, was once in their shoes, with nobody to act as his mentor.

"Not at all. Not at all," Ortiz said. "But once I started getting into the big leagues, I make a lot of friends and a lot of guys give me a lot of good advice."

So, when he gets the opportunity to act as a mentor -- coach, advisor, big brother, friend -- to