Émilie Jaumain died of a prion disease (variant Creutzfeldt-Jacobs disease, vCJD, the human equivalent of the “mad cow” disease) in 2019.

She was most likely infected in May 2010 while working in a French laboratory studying transgenic mice overexpressing prions. The contamination must have occurred when she pricked her thumb, through two pairs of gloves, with forceps used to manipulate mouse brains riddled with prions.

In November 2017, Émilie’s “descent into hell” (her husband’s words) began. Initially, the burning pain came: in her neck and right shoulder first, then in the whole right side of her body. She later endured depression, insomnia, confusion, muscle stiffness, and visual hallucinations. Eventually she lost her ability to talk and to move, and she passed away in June 2019.

She was diagnosed with vCJD three months before her death, upon analysis of her blood and cerebrospinal fluid (CSF) with a technique called protein misfolding cyclic amplification. This technology mimics the strategy used by the misfolded prion protein (the cause of CJD) to replicate: they induce the misfolding of the normally folded prion proteins. Émilie had been shown to carry a polymorphism in both alleles of the prion protein gene (a methionine at codon 129) which increases the susceptibility to CJD.

Post-mortem examination of Émilie’s brain confirmed the diagnosis of vCJD. This study, published in the New England Journal of Medicine in 2020, concluded that Émilie contracted the infection following the exposure to prion-contaminated material.