Researchers may have found cause of mad cow disease

PARIS – Researchers believe they have found the cause of mad cow disease, though on Wednesday they stressed the need to maintain precautionary measures to avoid a potential re-emergence of the illness.

Several hypotheses have been put forward over the cause of bovine spongiform encephalopathy, a neurodegenerative disease that was dubbed “mad cow disease” when it first appeared in the 1980s in the United Kingdom.

The illness belongs to a family of ailments involving misfolding proteins that are known as prions. These also exist in other diseases, such as scrapie in sheep and Creutzfeldt-Jakob disease in humans.

Researchers injected a scrapie variant into mice, producing the prion of bovine origin following genetic manipulation.

This allowed them to show not only that the illness had the ability to jump from one species to another but that the transmuted mice developed mad cow disease, according to an article in the Proceedings of the National Academy of Sciences.

The genetically modified mice are “a very good model, which works well in terms of knowing what would happen if one exposed cows to those prions,” said Olivier Andreoletti, a researcher with the French National Institute for Agronomic Research (INRA), which led up the study.

The results are explained by “the presence of quantities of classic mad cow disease” in unmanipulated form in the scrapie-variant prions that were injected, INRA stated.

“For the first time, these data bring an experimentally underpinned explanation to the appearance” of mad cow disease in the U.K. in the 1980s.

The disease then spread in cattle across Europe, North America and numerous other countries. The process was aided by the animals’ consumption of foodstuffs that included parts from the carcasses of animals that had been hit by the ailment.

Contact with products from infected cattle led to humans becoming infected with the prions that cause Creutzfeldt-Jakob disease.

From the 1990s, Europe introduced a slew of measures to counter the spread of the illness, including banning cereals mixed with animal parts, tougher surveillance of cross-contaminations and destruction of the highest-risk tissues, thereby eventually bringing the spread under control.

“These measures are still in place — but they are very expensive, leading in some quarters to calls for their elimination and “to resume recycling of good quality proteins” rather than throwing them away in what might be an alternative to soy imports, Andreoletti observed.

Post time: Dec-23-2019