As deer hunting seasons across the nation ramp up, wildlife officials are issuing new warnings and confirmations of chronic wasting disease, the brain-wasting animal disease informally called "zombie" deer disease.

Every state differs on hunting regulations and how they handle management of chronic wasting disease, but in recent weeks, wildlife officials in states including Nevada, Iowa, Wyoming, Pennsylvania and Tennessee have either warned hunters about the disease to prevent its spread to their state or confirmed new cases.

According to the Centers for Disease Control and Prevention, at least 277 counties in 24 states have reported chronic wasting disease in free-ranging deer, elk or other cervids as of August.

There are no vaccines or treatments available for the disease, which is always fatal. And while no cases have been reported in humans to date, some researchers worry it poses a risk to humans.

Here's what you need to know about chronic wasting disease and how to prevent it:

What exactly is chronic wasting disease?

CWD is a type of prion disease called transmissible spongiform encephalopathies.

The disease affects deer's brains and spinal cords through abnormal prion proteins that damage normal prion proteins, the CDC said. The cells collect and eventually burst, leaving behind microscopic empty spaces in the brain matter that give it a “spongy” look, according to the North Carolina Wildlife Commission.

Symptoms, which can take more than a year to develop, include drastic weight loss, lack of coordination, listlessness, drooling, excessive thirst or urination, drooping ears, lack of fear of people and aggression.

How does chronic wasting disease spread?

In deer, CWD spreads through contaminated bodily fluids, tissue, drinking water and food, the CDC says.

The disease was first identified in captive deer in the late 1960s in Colorado and in wild deer in 1981, the CDC said. According to the health agency, CWD could be more widespread than 24 states.

"Once CWD is established in an area, the risk can remain for a long time in the environment. The affected areas are likely to continue to expand," the CDC says on its website.

Is infected meat safe to eat?

Some infectious disease experts worry that if CWD were to infect humans, consuming infected meat would be the pathway.

"It is probable that human cases of chronic wasting disease associated with consumption with contaminated meat will be documented in the years ahead," Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, told state lawmakers earlier this year.

The CDC also says eating infected deer meat would be the most likely way for it to spread to people.

More:In 2005, about 200 people ate ‘zombie’ deer meat. Here’s what happened

About 7,000 to 15,000 animals infected with CWD are eaten each year, and that number could rise by 20% annually, according to the Alliance for Public Wildlife, which Osterholm cited in his testimony.

Scientists can't say for sure that CWD will cross over and infect humans, but as time goes on and more infected meat is consumed, the likelihood increases, Osterholm said.

"It's like a throw at the genetic roulette table," he said.

Don't touch roadkill

People shouldn't handle or eat meat from dead animals. Also, never shoot and handle a deer or elk that is acting strangely. If you see an animal that appears to be sick, take note of its location and contact wildlife officials.

Some states recommend hunters have deer or elk tested before eating their meat. But even a test can detect CWD only at a certain stage. There is not a test that can definitively say the animal is negative for the disease, Texas Parks and Wildlife notes. Information about what your state recommends is available from state wildlife agencies.

Wear gloves when field-dressing a deer

The CDC recommends wearing latex or rubber gloves when handing a hunted animal and its meat. Also, minimize the time spent touching organs such as the brain and spinal cord tissues. Never use household knives or utensils for field dressing. Always wash hands and disinfect hunting instruments after use.

Process meat individually

Hunters who typically have deer or elk commercially processed might want to ask whether their animals can be processed individually to avoid any chance of contamination.

"If you put this into a meat processing plant ... this is kind of a worst-case nightmare," Osterholm told lawmakers.

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