Fears ‘zombie deer disease’ could ‘pass to humans like mad cow disease’ after death of men

SCIENTISTS fear two hunters may have contracted a 'zombie deer disease' after eating infected meat.

The US pair died soon after eating deer meat which scientists believe could have carried chronic wasting disease (CWD).

They developed similar neurological symptoms seen in animals, raising concerns CWD could pass from deer to humans.

The disease attacks the brain and nervous system, leaving animals drooling, lethargic, stumbling, and stick-thin.

It's been dubbed 'zombie deer disease' due to the telltale blank stare of infected deer.

Some experts fear the illness could spill over to people in a similar way to mad cow disease back in the 90s.

But scientists at the University of Texas Health Science Center at San Antonio have examined the hunters' deaths in 2022 and their findings suggest the disease may already be spreading from animals to humans.

One of the victims discussed, a 72-year-old man, suffered ";rapid-onset confusion and aggression" as well as seizures.

He died within a month despite treatment.

After his death, he was diagnosed with sporadic Creutzfeldt-Jakob disease (CJD), a brain-wasting condition. Mad cow disease is another form of CJD, known as acquired CJD. 

"The patient’s history, including a similar case in his social group, suggests a possible novel animal-to-human transmission of CWD," they  published this month in the journal .

The hunter's friend also died from the disease, but the new study didn't share many details about his condition.

While the researchers are from Texas, details about where the men lived or hunted were not shared.

What is chronic wasting disease?

CWD is an incurable prion disease that affects animals, deer, elk, reindeer, sika deer and moose.

Prion diseases are a family of rare but aggressive neurodegenerative diseases that affect both animals and humans (CJD is a human prion disease).

'Prions' are a type of protein that can trigger normal proteins in the brain to fold in an abnormal fashion.

The abnormal folding of the prion proteins can lead to brain damage, severe disability, personality changes, difficulty with movement as well as other symptoms, characteristic of the specific prion disease.

While scientists still don't know a lot about prion diseases, they tend to be fatal.

CWD has been detected in 32 US states, as well as three Canadian provinces, South Korea, Finland, Norway and Sweden.

It may take over a year for infected animals to develop symptoms, and they can die before they start drooling or get the “blank stare”.

There is currently no effective treatment or vaccine for the disease.

Like CWD, CJD is also caused by abnormally folding prions.

In most cases, CJD develops "sporadically", but there is also a sub-type of CJD which can be inherited if one parent carries a mutation that causes prions to form in their brain during adulthood.

Acquired CJD - or mad cow disease - is spread to humans from animals through contaminated meat, from a cow that had bovine spongiform encephalopathy (BSE).

Most people affected die within a year of diagnosis.

In the latest study, the Texan scientists never confirmed whether the specific deer eaten by the hunters was ever tested for CWD.

And because it is so difficult to distinguish between the two diseases, the researchers could not prove the men had picked up the infection from the deer meat.

However, there was a possibility of transmission due to both hunters' history of eating meat from that infected herd, they said.

"Although causation remains unproven, this cluster emphasises the need for further investigation into the potential risks of consuming CWD-infected deer and its implications for public health," the team wrote. 

'CWD might infect humans'

Alarms were sounded in December after hundreds of deer in Yellowstone National Park were found to have been infected with the highly contagious illness.

The Wyoming Game and Fish Department tested meat from 6,701 deer, elk and moose in 2022, detecting the disease in about 800 samples.

Separate research published in Acta Neuropathologica found “CWD might infect humans, although the transmission barrier is likely higher compared to zoonotic transmission of cattle prions”.

The study found that while mice could become infected with the disease, it did not cause the same symptoms as in deer, which include poor coordination, appearing listless and tremors.