Environmentalists filed a lawsuit against the U.S. government on Tuesday in their effort to cease a federal wildlife refuge in Wyoming from going on feeding wild elk. They say this could lead to or worsen a spread of diseases in the large wildlife and livestock around Yellowstone National Park.

Among the diseases the environmentalists name is a chronic wasting illness that is the elk equivalent of mad cow disease. The suit also cites brucellosis, scabies and hoof rot.

Brucellosis can cause premature abortion in pregnant animals.

Chronic wasting disease causes brain lesionsis in elk, moose and deer and can lead to neurological sickness and death. There is no evidence that the disease can be transmitted to humans, but studies on the matter are underway.

There have been recorded cases of chronic wasting disease just 70 miles from the ecosystem that includes the National Elk Refuge in Jackson, Wyoming, and Yellowstone National Park. Environmentalists are worried that it could infect and kill animals in and around the park.

Wildlife biologists warn that feeding the animals that live together at the National Elk Refuge and at 22 other state feeding grounds in Wyoming is likely to increase the risk of an outbreak as regards the mentioned disease. Conditions at feed lots multiply disease rates up to 10 times those found in the wild because illnesses are passed rapidly among animals in close contact.