A French study succeeded in showing that scrapie, a disease similar to mad cow, could also affect humans.
For the first time, a study shows that scrapie can infect humans. Sheep scrapie is a prion disease, which is a fatal neurodegenerative disease that affects mammals. In humans, the most common form is classical Creutzfeldt-Jakob disease. The most famous prion disease is mad cow disease (bovine spongiform encephalopathy or BSE).
While the transmission of BSE to humans was already known, the ability to transmit scrapie to humans had never been proven. Olivier Andréoletti, from the National Veterinary School of Toulouse, and his colleagues succeeded for the first time in infecting a humanized mouse with the scrapie prion. Humanized mice are genetically modified mice, which make the human prion protein, and simulate the human organism.
Abnormal prions similar to those causing Creutzfeld-Jakob
Posted online, Tuesday December 16, by the magazine Nature Communications, the study explains that the researchers inoculated a dose of the disease directly into the brains of humanized mice. In the mice that survived 500 days, their brains were removed and extracts were inoculated into another batch of humanized mice. Result: A sample of scrapie prions was transmitted to some modified mice with an efficiency comparable to that of the mad cow disease prion.
Importantly, this transmission of scrapie prions has resulted in the spread of abnormal prions similar to those that cause human Creutzfeldt-Jakob disease. Although the study was conducted in humanized mice, the results suggest the possible ability of scrapie to infect humans.
Take precautionary measures
Even if no causal link has been established between exposure to sheep scrapie and certain cases of Creutzfeldt-Jakob disease and if we cannot speak of any threat to public health, “certain precautionary measures appear. impose yourself, remark Olivier Andréoletti at Monde.fr. This includes the continuation of epidemiological monitoring in humans and examinations in animals showing signs of scrapie. Above all, at a time when some are talking about lifting the obligation to withdraw specified risk materials from the food market, it is essential to maintain it. “
“Specified risk materials” means tissues and offal considered to represent a risk with regard to Subacute Transmissible Spongiform Encephalopathies, such as explains the Ministry of Agriculture. These are the eyes, the brain or even the spinal cord – in which the pathological prion is concentrated. Their withdrawal was implemented at European level in 2001.
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