Lab assistant Émilie Jaumain injured her thumb in 2010 and died in 2019 at the age of 33, probably of Creutzfeld-Jakob disease. | Image: ZVG

After someone working in a French lab for prion research was diagnosed with Creutzfeld-Jakob disease, five research institutions in France declared a three-month moratorium on working with prions as of late July 2021. In the 1990s, prions became known for triggering so-called mad cow disease, BSE. They are abnormally folded proteins that can transfer their abnormality to other proteins like a virus, and thereby destroy the way the brain functions. In human beings, this can lead to Creutzfeld-Jakob disease.

The case in France is the second of this kind in a short space of time. One staff member of a lab died back in 2019. It transpired that they had injured a finger nine years earlier with a contaminated object that had punctured their glove. Creutzfeld-Jakob disease can occur spontaneously in one out of a million people. Only after death can the precise type of the illness be determined.

“This is the right way to go in the circumstances”, Ronald Melki, a French biologist, told Science after the announcement was made. The magazine reported that the incident had only led to a single case of someone resigning because they were afraid. The Swiss prion researcher Adriano Aguzzi of the University of Zurich did not make any statement to Science about the cases in France, but he insisted that his lab only worked with mouse-adapted sheep prions. As yet, he said, none of these had ever been shown to be infectious to humans. When it became known in 2011 that mice can be infected through aerosols, he was “totally shocked” and thereupon introduced appropriate safety measures in his lab.