White-tailed deer in Maryland national parks have tested positive for the fatal Chronic Wasting Disease, the National Park Service announced Tuesday. Chronic Wasting Disease (CWD) is a contagious, fatal disease of deer, moose, and elk that causes physiological and behavioral changes, starvation, and death. Some of these changes include depression, altered gait, head tremors, and circling, leading infected deer to be unofficially dubbed as ‘zombie deer’.

The discovery was made during deer reduction operations at the Antietam and Monocacy National Battlefields in northern Maryland. The operations are conducted to protect and restore vegetation and preserve historic landscapes, during which officials monitor wildlife health, including testing deer for CWD.

CWD was initially found in Colorado and Wyoming in the 1960s and 1970s, and was only identified in Maryland in 2010. However, it is only in 2024, with recent monitoring, that CWD has been found in deer in the state’s national parks. Officials noted that CWD spreads by direct animal-to-animal contact or indirectly through contact with infected particles in the environment, such as feces, soil, and vegetation.

While CWD is not known to infect humans or domestic animals, park visitors are advised to avoid eating venison from CWD-positive deer and meat from other CWD-infected animals. They are also recommended to avoid sick or dead wildlife in the park and to report any findings to an NPS employee as soon as possible.