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No kidding! Does "zombie deer disease" threaten humans?


WASHINGTON – It sounds like a plot of "The Walking Dead".

The deer is contracting a mysterious disease. Symptoms include vacant glances, thick saliva, exposed ribs, drooping heads – but no behavior outside the normal deer's range of activity. They can live two years like this. Then, one day, they break, become too aggressive – so the caricature of "zombies" – before dying.

The great concern is that people have eaten infected deer meat, which raises fears that the plague will cross species.

The real name of what is called "zombie deer disease" is "chronic disease of dieback". It was first observed in 1967 in Fort Collins, Colorado, and infected herds in 24 states, as well as in Canada, South Korea and Norway, Centers for the Control and Prevention of Diseases. disasters.

Chronic Wasting Disease, or CWD, is passed from one animal to another through prions, misfolded proteins that cause other proteins to fold poorly around them. Different prion diseases tend to harm only certain species, but can evolve to overcome these limitations.

The following states have reported the disease: Arkansas, Colorado, Illinois, Iowa, Kansas, Maryland, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, New Mexico, New York, North Dakota, Pennsylvania, South Dakota, Tennessee , Texas, Utah, Virginia, West Virginia, Wisconsin and Wyoming. As of February 19, 42 counties in Nebraska reported a CWD.

In some herds, up to half of the animals carry prions.

But direct contact is not the only way to transmit prions. Sick animals and cadavers can spread prions through plants and soil, which could be covered with deformed proteins for years to decades.

Although the disease has not been reported in humans and scientists have no conclusive evidence that infected meat has ever harmed humans, wildlife protection officials Colorado and Pennsylvania insist that hunting regulations be safe.

And there is more reason to worry.

A Canadian study added to the concern that eating infected deer could spread the disease to other species – including people. A prominent researcher on prions, Stefanie Czub, of the Canadian Food Inspection Agency, discovered that three of the five monkeys fed on infected meat had tested positive for the disease. chronic wasting.

As part of the research, 18 macaque monkeys were exposed to CED in a variety of ways: injection of material into the brain, contact with the skin, and feeding of infected meat. This is the first time that the disease is transmitted to primates through the consumption of deer meat.

"It has long been assumed that chronic wasting is not a threat to human health," Czub said. "But with the new data, it seems like we need to revisit this view to a certain extent."

The research was funded by the Alberta Prion Research Institute at the University of Calgary and began in 2009.

The prions were at the origin of the "mad cow disease". According to the Food and Drug Administration, 231 people died while eating beef infected with "mad cow disease".

Mark Zabel, associate director of Colorado State University's Prion Research Center, said prions involved in "zombie disease", which scientists have known for only 50 years, are likely still in the process of evolve. Zabel thinks the only way to get rid of CWD prions is to make controlled fires.

According to Michael Miller, senior wildlife veterinarian for Colorado Parks and Wildlife, mule deer infection has more than tripled by the end of 2017, and the MDC continues to prevail in Colorado.

"What we have seen in recent decades is that the virus is spreading slowly in wild deer populations," said Peter Larsen, assistant professor of veterinary science at the University of Minnesota. It also spreads among captive deer, elk and reindeer, which are transported around the country and abroad to hunting ranches, children's zoos and Christmas themed farms. That's how the disease ended up in South Korea, Larsen explained.

On March 13, 2005, a fire company in Oneida County, NY, fed meat from a deer tested positive for chronic debilitating disease between 200 and 250 people . The company did not know that the meat came from a sick deer. Lab tests for one of the deer served came back later – positive for the MDC.

Over time, the Oneida County Health Department oversaw the group's health through a monitoring project. About 80 people who ate venison agreed to participate. In collaboration with the State University of New York-Binghamton, health experts have been speaking with the group over the past six years to determine if they develop unusual symptoms.

In a study published in the public health journal Public Health, researchers found that the group had "no significant changes in health status," although they reported eating less venison after all. l & # 39; test. Otherwise, the conditions observed, including vision loss, heart disease, type 2 diabetes, weight changes, hypertension, and arthritis, have all been accounted for in old age.

Read the full study published in "Microbiology and Molecular Biology Reviews".

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