Two deer hunters diagnosed with rare and fatal brain disease, raising concerns about chronic wasting disease (CWD)

Two friends hunting deer together at the same lodge have died from an extremely rare brain disease, raising concerns that they may have contracted the disease from contaminated deer meat.

A team of neurologists at the University of Texas Health Science Center in San Antonio presented an example He said at last week's meeting that the deer herd surrounding the lodge is known to be infected with chronic wasting disease (CWD). This is a fatal brain disease in deer caused by misfolded prion proteins.

“The patient's medical history, including similar cases within the patient's social group, suggests the possibility of a new animal-to-human transmission of CWD,” the researchers wrote.

But scientists at the National Prion Disease Pathology Surveillance Center and the Centers for Disease Control (CDC), who have been monitoring this type of disease for decades, say venison and chronic wasting disease may be involved in the deaths. said to be very low. Of the two men.

“We disagree that these cases were caused by the consumption of deer meat,” said Ryan Maddox, a senior epidemiologist and deputy director at the CDC.

Scientists have long worried that chronic wasting disease could be transmitted from deer to humans. Not only would it pose a risk to human health, it would be devastating to the outdoor economies of Minnesota, Wisconsin and many parts of the Midwest where deer hunting is part of the culture.

The disease is untreatable and always fatal in deer.It is from sick family It has puzzled scientists for years. It is not caused by viruses or bacteria. Rather, prion proteins in infected brains fold in the wrong direction, disrupting connections and destroying cells. Misfolded proteins self-replicate, increasing damage to the brain until it no longer functions.

There have been no known cases of chronic wasting disease spreading to humans since the disease was discovered on captive hunting farms in the 1980s, and it has rapidly spread to half of the U.S. wild deer population over the past two decades. Did.

Other prion diseases such as bovine spongiform encephalopathy and mad cow disease have also spread to humans. In the 1990s, mad cow disease caused a variant of Creutzfeldt-Jakob disease in people who ate infected meat. Creutzfeldt-Jakob disease is a rare prion disease that affects about 1 in 1 million people each year.

In 2022, a 72-year-old man “with a history of consuming meat from deer populations infected with CWD” began showing signs of Creutzfeldt-Jakob disease, neurologists in Texas said in a presentation.

A friend of his, who hunted in the same cabin and ate venison from the same herd, had just died of the disease. After the 72-year-old man died, an autopsy confirmed the disease, they wrote.

There is no conclusive evidence that chronic wasting disease is the cause of the men's illness. “This cluster highlights the need for further investigation,” they wrote.

Researchers did not say where the men hunted. One of the neurologists, Dr. Sarah Horn, declined to be interviewed and reiterated in a statement that the information in the report was a presentation of a case, not a complete research study.

“The conclusion from that presentation was that there are no proven cases remaining to date,” she said.

CDC's Maddox said the agency investigated both incidents in 2022.

“We feel strongly that they are part of the normal number of cases we are seeing,” he said. “Many Americans hunt and even eat venison, and some people develop it sporadically. [Creutzfeldt-Jakob] Maybe it's a coincidence, maybe it's not. ”

“The man's age, symptom progression, and brain changes were all consistent with what is normally seen in a typical Creutzfeldt-Jakob case,” Maddox said.

When mad cow disease infected humans and caused a variant of Creutzfeldt-Jakob disease, the patient's age, symptoms, and visible damage to the brain in patients who ate infected meat and became ill were closely linked to the infection. The patient was clearly different from the previous patient. Not so, said Dr. Brian Appleby, director of the National Prion Disease Surveillance Center.

No one knows exactly what chronic wasting disease looks like in humans, but the hope is that autopsies will be able to tell the difference, Appleby said.

Appleby said he agrees with researchers that the possibility of human infection with CWD needs to be closely monitored and investigated.

He said the more a disease spreads in the wild, the more opportunities there are for variants to develop that can infect humans.

CWD has been found in deer in several Minnesota counties.What the country provides free testand hunters are urged to have their deer tested for disease before consuming the meat.