PRIONS THAT CAUSE CHRONIC WASTING DISEASE can pass from wild animals to plants - from plants to cows - from cows to humans - MAD COW DISEASE is also caused by prions and is blamed for ALZHEIMER'S disease among meat eaters

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KEY POINTS

• Chronic wasting disease is a prion disease of cervids (deer, elk, moose) and humans.
• Animals leave prion-contaminated feces and urine on the grass.
• Plants can take up prions from the soil and transmit them to grazing animals.
• Cows can get contaminated with prions from the grass they eat, and then pass it on to humans.
• Studies show that prions can bind to plants and be taken into the roots, where they may travel to the stem and leaves.
• Neither washing nor cooking plants will eliminate the contamination.
• Just as cooking contaminated beef did not halt the spread of bovine spongiform encephalopathy (mad cow disease), another prion-caused disease
• Keeping cervids out of grazing or growing fields could help mitigate the contamination.
• Prions have been held responsible for a number of degenerative brain diseases, including mad cow disease, Creutzfeldt-Jakob disease, fatal familial insomnia, kuru, and an unusual form of hereditary dementia known as Gertsmann-Straeussler-Scheinker disease.

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Virology Blog - Chronic wasting disease is a prion disease of cervids (deer, elk, moose) that is potentially a threat to human health.

A role for environmental prion contamination in transmission is supported by the finding that plants can take up prions from the soil and transmit them to animals.


A concern is that prions of chronic wasting disease could be transmitted to cows grazing in pastures contaminated by cervids.

Consumption of infected cows would then pass the disease on to humans.

When deer are fed prions they excrete them in the feces before developing clinical signs of infection, and prions can also be detected in deer saliva.

In the laboratory, brain homogenates from infected deer can transmit the disease to cows.

To determine whether prions can enter plants, wheat grass roots and leaves were exposed to brain homogenates from hamsters that had died of prion disease.

 

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The plant materials were then washed and amounts of prions were determined by protein misfolding cyclic amplification.

 

Prions readily bound these plant tissues, at low concentrations and after as little as 2 minutes of incubation.

 

Mouse, cervid, and human prions also bound to plant roots and leaves.

 

When living wheat grass leaves were sprayed with a 1% hamster brain homogenate, prions could attach to the leaves and be detected for 49 days.

 

To determine if prions in plants could infect animals, plants were exposed to brain homogenates, washed thoroughly, and then fed to hamsters.

 

The positive control for this experiment was to feed hamsters the brain homogenates.

 

All animals fed infected plants or brain homogenates succumbed to prion disease.

 

Plants can also take up prions from animal waste. This conclusion was reached by incubating leaves and roots for 1 hour with urine or feces obtained from prion-infected hamsters or cervids.

 

Prions were readily detected in these samples, even after extensive washing.

 

Experiments were also done to examine whether plants could take up prions from the soil. Barley grass plants were grown on soil that had been mixed with hamster brain homogenate, and then 1-3 weeks later, stem and leaves were assayed for the presence of prions.

 

Small amounts of prions were detected in stems from all plants, while 1 in 4 plants contained prions in leaves, at levels that should be able to infect an animal.

 

These results show that prions can bind to plants and be taken into the roots, where they may travel to the stem and leaves.

 

Therefore it is possible that prions excreted by deer could pass on to other animals, such as grazing cows, or even humans consuming contaminated plants (illustrated – image credit).

 

Cooking plants will not eliminate infectivity, just as cooking contaminated beef did not halt the spread of bovine spongiform encephalopathy.

 

Keeping cervids out of grazing or growing fields should be considered as a way to manage the risk of prions entering the human food chain.

Source
http://www.virology.ws/2015/06/25/prions-in-plants/

RELATED

PRIONS are a small proteinaceous infectious disease-causing agent that is believed to be the smallest infectious particle.
A prion is neither bacterial nor fungal nor viral and contains no genetic material.
Prions have been held responsible for a number of degenerative brain diseases, including mad cow disease, Creutzfeldt-Jakob disease, fatal familial insomnia, kuru, and an unusual form of hereditary dementia known as Gertsmann-Straeussler-Scheinker disease.
Source
http://www.medicinenet.com/script/main/art.asp?articlekey=5047


October 2011 -  Could Alzheimer's disease be infectious like mad cow disease?

The brain damage seen in some cases of Alzheimer's disease could have its roots in an infectious prion-like disease, such as that seen in bovine spongiform encephalopathy (mad cow) and its human form Creutzfeldt-Jakob disease (CJD), according to an international study published this week in the journal Molecular Psychiatry that was led by the University of Texas Medical School at Houston in the US.

 

Study results showed that mice injected with Alzheimer's brain tissue developed plaques and other hallmarks of the disease.

Read more
http://www.medicalnewstoday.com/articles/235493.php

 

More articles on plants and trees on this blog

http://ottersandsciencenews.blogspot.ca/search/label/Plants%20and%20Trees

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