A Second Person in France May Have Caught Deadly Prion Disease From Lab Exposure

The new case, the second in three years possibly linked to research on prions, has led to a temporary shutdown of prion research by several major labs.

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Public research labs in France are temporarily halting their work into prions, after at least two employees are believed to have contracted a rare but universally fatal prion brain disease. One woman has since died, almost certainly after having been exposed during a lab accident in 2010, while the second is reportedly still alive, and it is not yet confirmed whether her illness was caused by lab exposure.

Prions are a type of protein commonly found in the brain. They seem to serve some important but still unclear natural function. But prions can also turn into a misfolded form of themselves, one that slowly turns other “normal” prions around them rogue, too. Over time, this cascading effect spreads throughout the brain and destroys it, leaving behind telltale sponge-like holes that can be spotted under a microscope. Prion diseases are very rare, but there are no available treatments, and people usually die within months to a year of the onset of symptoms, which typically include dementia and motor impairment.


The first case, now known to be a woman named Émilie Jaumain, began experiencing symptoms in late 2017. She was suspected to have variant-Creutzfeldt-Jakob disease (vCJD), a form of CJD spread through exposure to prions from other animals. The first cases of vCJD were discovered in the 1990s, after people ate meat from tainted cows and then developed a prion disease, which was given the morbid nickname of mad cow disease. The diagnosis was confirmed in a brain autopsy following Jaumain’s death 19 months later. She was only 33-years-old.

Though there is room for the possibility that Jaumain contracted her vCJD elsewhere, the strongest likelihood by far is that she caught it during a lab accident in May 2010, when she pierced her skin with forceps that were handling frozen, prion-infected brain samples from mice genetically engineered to develop human prions. French researchers reported the tragic case last year.


Jaumain had been working at a lab run by the National Research Institute for Agriculture, Food and Environment (INRAE), one of France’s public research organizations, when she presumably got exposed. On Tuesday, the INRAE revealed that yet another person working at one of their labs had recently been diagnosed with CJD as well. The discovery of the second case was enough to compel the INRAE and four other public research organizations to impose a three-month moratorium on prion research, while an investigation is ongoing into the circumstances of the second case.

The moratorium “will make it possible to study the possibility of a link between the observed case and the person’s former professional activity,” the INRAE and other organizations said in a joint statement released yesterday.


The woman in the second case, a lab worker, has since retired and is still alive, according to reporting Wednesday from Science Magazine. It’s not known which form of CJD she has, which could be a crucial clue as to the origin of her illness. Most cases of CJD are sporadic, seeming to arise for no specific reason. Some cases are familial, found in people with specific inherited mutations. And vCJD is most often associated with transmission from another animal, typically cows. These forms have noticeably different patterns of presentation, with sporadic cases appearing most often in older people, while vCJD tends to strike younger patients. Theoretically, though, all forms of CJD could be transmitted through close enough exposure to infected brain matter (another prion disease, kuru, infamously spread through cannibalism).

Jaumain’s friends and colleagues have called for far-reaching improvements in lab safety during prion research. They’ve started an advocacy group in the wake of her death called Emilys Association, while her family is currently pursuing criminal and administrative legal action against the INRAE over her death. While the specific lab she worked at was cleared of wrongdoing by several investigations, according to Science, her family’s lawyers contend that there have long been inadequate safety measures taken during this dangerous work in the country’s research facilities. Should this new case turn out to be lab-related, they may have a point.