painful infectious disease that can transform the brains of deer, elk and moose in a "Swiss cheese" is distributed in at least 24 countries – and some experts warn that eventually can enter in people.
Known as chronic wasting disease – and colloquially referred to as "zombie deer disease" – the fatal progressive neurodegenerative disease was first identified in the 1960s. Like mad cow, chronic disease loss spreads through prions, zombie-like pathogenic proteins that are not alive and can not be killed. When they infect an animal, they eaten his brain, causing a cascade of symptoms that resemble dementia and ultimately lead to death. While the disease is still rare, researchers believe it is more widespread than ever because of how people trade with deer and other ungulate mammals.
"What we have seen over the past few decades is that it is spreading slowly in the wild. populations of deer, "says Peter Larsen, assistant professor of veterinary science at the University of Minnesota, who studies the pathogen. It is also distributed among closed deer, elk and reindeer, which are transported across the country and abroad to hunt ranch, zoo zoos, and Christmas-themed farms. Thus, the disease ends in South Korea, Larsen said. (This is also found in Canada and Norway.)
When new outbreaks begin, they are almost impossible to hold because, unlike viruses and bacteria, prions can not be killed and there is currently no good way to find them.
Researchers have long been wondering whether the disease, like a mad cow, can make the leap to people. (The Crazy Cow in Humans is known as Creutzfeld-Jacob's disease.) Late last summer we received a preliminary and frightening response. In an article published in Emerging Infectious Diseases researchers from Scotland and Canada have shown by a petri dish experiment that sick animal precursors can actually infect human cells. There has been no direct evidence of human disease ever since. However, this study prompted Michael Osterholm, director of the Center for Research and Policy on Infectious Diseases at the University of Minnesota, to compare the chronic extinction of the disease with the mad cow recently. Osterholm also warned the British government about the cow's risks, before hundreds of people were infected in the UK and around the world in the late 1
Let's go through what we know about this emerging infectious disease.
1) What is "Zombie Disease"?
Officially called chronic disease loss, zombie disease is a fatally progressive neurodegenerative disease that is thought to affect deer, moose, reindeer and moose. He was found in deer in Colorado in the 1960s and since then has been an interesting scientist. The disease is caused by prions – which are not viruses or bacteria. Prions are almost indestructible pathogenic proteins that trigger cells, especially in the brain and spinal cord, to fold unusually and start to wrinkle. When this happens, infected animals begin to develop many terrible symptoms – dementia, hallucinations, and difficulty in walking, talking and eating. Animals eventually become unstable and disoriented. These symptoms worsen over time and, as there is no cure, they always lead to death.
The reason why the disease gets the official name – Chronic Loss of Disease – is that when Prions catch up with an animal, it begins to lose weight and lose weight. Prions "turn the brain into a Swiss cheese," says Larsen.
But Larsen called "zombie disease" a miserable and potentially misleading name. "I have seen only one deer who died from [chronic wasting disease] and was exhausted," he said. – There are no zombie-like symptoms. Instead, the symptoms are what you expect to see from a very sick animal: thin, weak and unable to function normally.
"It is important to remember that [this] is a neurodegenerative disease – not a Hollywood zombie."
2) How is it spread in animals? An animal with chronic disease can spread prions to other animals by direct or indirect contact with body fluids such as stools, saliva, blood or urine. This means that the disease can spread if the infected deer is injured, for example, and its blood touches an uninfected animal; or if the healthy animal comes into contact with the soil, food or water that has been contaminated by sick deer.
That's not all, Larsen said. Since the prions are so healthy, they can survive in the environment – farms, forests – even for years. "So let's say you have a stag with chronic disease loss, and he began to shed [prions] in urine, faeces, saliva." If this deer dies on the forest floor, the prions can survive and connect with the soil where the plants are dipped. them. These plants can then spread the prions through their leaves, says Larsen.
So it spreads in the wild, slowly. And every year we see more and more cases of chronic disease loss. "
3) How would it spread to people?
There have been no documented cases of chronic disease wasting in humans – but researchers believe it is possible and becoming more and more likely as infections are becoming more prevalent in animals. is indirect. In laboratory experiments, scientists have shown that the disease can spread to monkeys and mice that carry human genes, say centers for disease control and prevention. In an unpublished study, the macaques – a species of primates genetically similar to humans – who were fed with infected meat, are infected with the disease.
"Experiments take place when researchers take environmental samples, like rocks or pieces of wood that have prions on them," Larsen says. "Then they place these infected objects in cells with transgenic hamsters and the hamsters develop the disease."
Finally, in another recently published study, the researchers found that the chronic disappearance of the disease was infected with human cells in a petri dish. The CDC says these experimental "worry that [chronic wasting disease] may pose a risk to humans and suggest that it is important to prevent people from being exposed to [the disease]." The most likely way to do this is if a person , as a hunter, ate contaminated meat.
This brings us to another disturbing fact about chronic disappearance of the disease, "prion, you [cook it off]. The temperatures required for its destruction are far beyond what we can cook – said Larsen.
The only way to make prions non-infectious is by using lye, a strong alkaline solution, which drastically changes the pH balance and autoclaving – or their treatment under pressure at 270 degrees Fahrenheit. "Most people do not have access to this approach," said Larsen and "the point is that it is difficult to manage [infectious] prions in the environment, because we do not know exactly where they are hiding. "
4) Where is a zombie disease in the United States
Well, we know only where a chronic disease is can only be diagnosed after they have died (researchers must have access to the tissues that are deep in the brain of the animal and test them.) However, animals can carry pathogens for years and show no signs or symptoms. "This deer can go on a 40-kilometer trip by sprinkling [infected] the prion in his stools or urine," Larsen said. "If we go and say that this is a deer on this point on the map, what you do not see on this map is wherever it has been in the last two years."
Since January 2019, 251 counties in 24 states have reported chronic disease wastage in wild-caught reindeer, the CDC reported. You can see them here:
Again, however, researchers consider that the extent of the spread is very wider. The CDC also notes that some countries have better animal disease surveillance systems than now, so the current map may be more a reflection of where the discovery is the strongest (and past disease) than where the deadly prions are currently being distributed in the United States.
5) Can we stop spreading the disease?
Since there is currently no way to eradicate and cure the disease, researchers recommend that countries where they are known to spread are trying to keep it by identifying diseased animals.
Now, here is another problem: the tools available for this are now very limited. Diagnosis for disease detection in animals is not always accurate, not all countries have access to them and, again, they can only confirm the presence of an animal infection after it is already dead. It can take days or weeks to get results. This means that the illness may be on the move for some time before someone knows it is there.
Jeremy Saffers, a veterinary pathologist at the University of Minnesota, has recently begun the country's legislators to fund research to develop better diagnostic tools and to help scientists respond to basic issues of chronic disease extinction . Here are Sheffers, who spoke before the Mail in Minnesota:
We have to find infected animals before our death, but we have no test. […] We need to know how other animals move to the environment, but we have no test of it.
We need to know if the local meat shop is dirty and can be effectively cleaned, but we have no test for it. We need to know if prions move from soil to plants and are potentially infectious, but we do not have a test for it. … I want to know how much is in the soil and I want to know how much it takes to infect something, but we do not have a test for it.
All hunters need access to a test that can easily buy and quickly find CWD in their deer before they are cut into 100 pieces and fed into their family. These hunters do not have access to a test.
6) How can humans protect animals and themselves?
Health officials are most concerned about the potential of hunters to be exposed to the disease through animals carrying prions. So, anyone who is hunting in areas where chronic disease is known to be spreading should take the following precautions, according to the CDC:
- There is no shooting, handling, or feeding with elk or elk that seems unhealthy or "act oddly".
- When wearing (or removing the organs of) a pursued animal wearing latex or rubber gloves, avoid touching animal organs – especially cerebral and spinal tissues – and avoid using home-made utensils.
- Take the deer or moose meat tested for prion disease before you eat the meat. However, the CDC warns that since the diagnostic tools for the disease are still limited, "the negative test result does not guarantee that a single animal is not infected" with a chronic disease, but "may reduce the risk of exposure." 19659046] When the meat is handled commercially, ask the butcher if they process and process multiple animals simultaneously (to avoid cross-contamination).
Well, the users of game meat, like deer, and the restaurants that serve it? There was no soothing answer to that.
He warned that anyone eating game meat or a restaurant serving game asks where the meat is. And restaurants need to make sure their meat is free of disease. But again, in practice, this is not easy because of how long it takes to get results from the diagnostic tests.
"If you are a hunter and shoot deer to feed your family or sell, are you going to wait two?" Larsen asked. "How do you keep the meat fresh?"
So while consumers may have the right to know if their meat has been contaminated with pathogenic prions, there is currently no effective way to get an answer.
"People have been interacting with a deer for centuries," Larsen said, "for food, sports, or just watching them in the wild." But this tradition is "attacked now because of this pathogen."