France has issued a temporary moratorium on all research into prion diseases by public research laboratories for at least three months. The decision was made after at least two employees are thought to have contracted a rare and fatal prion brain disease after working in labs that handle prions.
Prions are a class of misfolding, infectious proteins that cause fatal brain disease. The moratorium has been issued after a retired National Research Institute for Agriculture, Food and Environment (INRAE) lab worker who had handled prions in the past developed Creutzfeldt-Jakob disease (CJD), the most common prion disease in humans, for which there is no cure. Though it has not been confirmed, an investigation has begun on whether the patient may have contracted the disease on the job.
While the origin of the disease is not certain, this could be the second known case of someone catching a prion disease in a French lab run by INRAE. In June 2019, Émilie Jaumain died at age 33 after being infected with prions in 2010. Jaumain, an assistant engineer, pricked her thumb during an experiment with prion-infected mice leading to her eventual death years later. Her family is suing the INRAE for manslaughter and endangering life.
After Jaunmain's diagnosis, government inspectors ran a general inspection on how prions are handled in France and found that all the visited labs had good regulatory compliance, and the research teams understood how to minimize the risks involved. That said, changes were implemented to make it safer, with better cut-resistant gloves and introducing plastic and disposable scissors and scalpels to reduce sharp instruments.
Jaumain contracted the disease due to the lab accident, where she had been given latex gloves instead of pierce-proof gloves, a 2020 paper in the New England Journal of Medicine concluded. She had variant CJD due to bovine spongiform encephalopathy (BSE), commonly known as mad cow disease. Given that the European outbreak of BSE finished in 2000 with no more cases of the variant Creutzfeldt–Jakob disease, it is unlikely that Jaumain contracted it via food. INRAE only recently admitted the likely link between her death and the lab accident.
Four out of five cases of the disease happen with no known causes, with the remaining fifth being either genetic or from transplantation of infected human tissue. The difference between the regular Creutzfeldt–Jakob disease and the variant can only be assessed after death by looking at brain tissue post-mortem.
Lab infections can occur with many pathogens so there are many safeguards in place when dealing with dangerous materials. Prions, however, are particularly worrying as CJD’s average incubation period is about 10 years, so it takes a very long time for the infection to reveal itself, which is inevitably always too late.