What is 'Zombie deer disease' spreading in US, and why are scientists concerned over its transmission to humans?

Scientists in the US have warned that Chronic Wasting Disease (CWD) spreading among wildlife across North America, could also transmit to humans. Also known as 'zombie deer disease', the disease leaves animals confused and drooling, and was first discovered in Yellowstone National Park in November. The disease has been detected in 800 samples of deer, elk, and moose across Wyoming. 

Experts have regarded CWD as a ''slow-moving disaster'' and are actively advising governments to prepare for the chances of its transmission to humans. As per the Centers for Disease Control and Prevention, the disease has been detected in 31 states in the US.

''The mad cow disease outbreak in Britain provided an example of how, overnight, things can get crazy when a spillover event happens from, say, livestock to people. We're talking about the potential of something similar occurring. No one is saying that it's going to happen, but people need to be prepared,'' CWD researcher Dr Cory Anderson told The Guardian.

No known case of CWD in humans has ever been registered so far. ''These studies raise concerns that there may also be a risk to people. Since 1997, the World Health Organization has recommended that it is important to keep the agents of all known prion diseases from entering the human food chain,'' states the CDC website.

What is Zombie Deer Disease?

'Zombie Deer Disease' also known as Chronic wasting disease (CWD), is a contagious and fatal disease that affects cervids, a group of animals that comprises deer, elk, caribou, reindeer, and moose. 

It is triggered by a malformed protein (prion) which collects in the brain and other tissues causing physiological and behavioral changes, emaciation, and finally death. It is transmitted by direct animal-to-animal contact or indirectly through contact with infectious particles moving in the environment such as faeces, soil, or vegetation. Animals can also become infected if their feed or pasture is affected by this virus. 

As per the Centers for Disease Control and Prevention, it may take over a year for symptoms in the deer to show. It usually begins with the deer drastically losing weight and losing all energy. Currently, CWD does not have any cure or vaccine available,