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PHILADELPHIA (CBS/CNN) — Cases of “zombie deer disease” are spreading across the country, including Pennsylvania. Known as chronic wasting disease, the disease rots the brains of deer, elk and moose, causing them to act lethargic and less afraid of humans before dying, the Centers for Disease Control warns.

Chronic wasting disease has been detected in wild deer, elk or moose in 24 states, with the CDC warning hunters to avoid handling or eating potentially infected meat.

The CDC has found the disease in five Pennsylvania counties, but it has not spread to New Jersey and Delaware at this time.

The disease affects the central nervous system and animals can show signs of drastic weight loss, lack of coordination and listlessness. It can make them more aggressive and less afraid of human contact, the center says.

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It’s in the same family of disease as Creutzfeldt-Jakob disease, which the CDC describes as “a rapidly progressive, invariably fatal neurodegenerative disorder.”

The center says scientists believe the contagious disease is passed between animals through bodily fluids.

Currently, there is no evidence the disease can spread to humans, but the CDC warned hunters to be cautious around potentially infected animals.

It advised people not to handle or eat meat from deer and elk that seem sick or have been found dead. It says latex or rubber gloves should be worn when handling the meat and contact kept to a minimum — especially when handling organs such as the brain or spinal cord.

In deer and other cervids, the disease has an incubation period of over a year, with some animals not showing symptoms for years after being infected, the CDC says. But the disease is always fatal.

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The Wyoming Game and Fish Department says animals will test positive for the disease long before its clinical signs appear “and the majority of CWD positive animals that are harvested appear completely normal and healthy.”

The disease was first found in captive deer in Colorado in the 1960s and in wild deer in 1981.

Cases of the disease have also been reported in Canada, Norway and Finland.

(©Copyright 2019 CBS Broadcasting Inc. All Rights Reserved.The-CNN-Wire™ & © 2019 Cable News Network, Inc., a Time Warner Company contributed to this report.)