An emergency rule passed this month by the state's Natural Resources Board will change the way many hunters handle the deer they harvest.

It's aimed at reducing the spread of chronic wasting disease, which is contagious and fatal to deer.

CWD was first detected in southwestern Wisconsin in 2001, and since then it's spread and increased in prevalence in the state.

With CWD infections in captive deer herds taken into account, the DNR now considers 55 of Wisconsin's 72 counties as CWD affected.

With the start of archery season just a few weeks away, efforts to slow the spread of CWD are intensifying in Wisconsin.

"What it's about is restricting the incidental movement of chronic wasting disease, disease agents that could spread it to a new part of the state," says Jeff Pritzl, DNR Regional Wildlife Biologist. "Where we're standing right here in Green Bay, we're about as far away from wild occurring CWD in the state as we can be, and frankly we want to keep it that way."

This month, the Natural Resources Board approved an emergency rule that puts tight restrictions on hunters transporting their deer.

"If it's a CWD-affected county -- and over half of the counties in the state are -- a deer carcass can’t leave that county unless it's going to a commercial meat processor or a taxidermist," says Pritzl.

That means hunters otherwise must quarter their deer, or bone it out, before moving it out of that county.

"The issue is if someone is doing their home processing, which is a great thing to do, but if they take that deer, and the scraps go out in the back 40, and it was a positive animal, now you've just introduced the disease agent to a new area," says Pritzl.

"What we have learned over the years is the prion, which is the agent of the disease, which is a deformed protein, is very resistant in the environment and can exist for at least five years on the ground. That agent as a protein can actually be taken up into vegetation. It's in the soil, some plants can take it up, and so animals can consume it," Pritzl continuesl.

Pritzl considers the new rule similar to rules boaters must follow to prevent the spread of invasive species, and he feels the vast majority of hunters will comply.

He says the DNR is in the process of creating a video to show hunters how to quarter their deer in the field.