A young woman in France developed a fatal brain disease almost eight years after she accidentally cut her finger while handling mouse brains in a lab.
Her death was not caused by a bacteria, a fungus, a virus, a parasite, or some kind of chemical agent, but through exposure to prions: a misfolded infectious protein that can trigger typical proteins in the brain to fold abnormally.
Reported in the New England Journal of Medicine, the story begins in May 2010 when the 24-year-old was working in a research laboratory in France where she handled frozen mouse brains that had been artificially tweaked to contain a human prion protein. While working with the samples, she stabbed her thumb through a double pair of latex gloves with a sharp pair of forceps used to pick up the brain sections. A few drops of blood were produced, but the injury appeared to be fairly minor.
Then, in November 2017, she started to experience an unusual burning pain down her right shoulder and neck. Over the following year, her symptoms worsened and she started experiencing depression, anxiety, forgetfulness, and even visual hallucinations. Tragically, the patient died 19 months after the onset of symptoms.
By analyzing the patient’s cerebrospinal fluid and blood, the doctors concluded she was suffering from variant Creutzfeldt-Jakob disease (vCJD), which was later confirmed during her postmortem. This is a rare condition that’s caused by a mysterious infectious agent known as a prion (or proteinaceous infectious particles).
Surprisingly little is known about prion diseases, although scientists do know they arise when certain proteins found on many types of cells begin to misfold in the brain. These misfolded prions can run amok by changing the shape of other neighboring proteins, which go on to become misfolded prions, further spreading the “damage”. Unlike other infectious agents, such as bacteria, fungi, or a virus, they do not contain any DNA or its relative RNA.
Cases of vCJD are exceptionally rare. Just a few hundred cases of vCJD have ever been confirmed, the majority of which we’re linked to the BSE (commonly known as “mad cow disease”) outbreak that originated in the UK during the 1990s and 1980s. In most vCJD cases, humans acquire the misfolded prions by ingesting brain tissue from animals infected with non-human prion disease. It was suspected that the woman could have eaten contaminated beef from this UK crisis, although the case study concludes the risk of this is “ negligible or nonexistent” given the timing of the illness.
Live Science points out that the family of the patient accused the lab where the accident occurred of manslaughter. French media reports from 2019 say the family argued the safety measures at the laboratory "were not up to standard" and she should have been provided with "cut-resistant gloves" not just latex gloves.
The new case study concludes by saying: "Such cases highlight the need for improvements in the prevention of transmission of variant CJD [vCJD] and other prions that can affect humans in the laboratory and neurosurgery settings."