Lab Tech Develops Fatal Brain Condition

October 15, 2020

A young lab technician in France has contracted a rare and fatal brain disease after accidental exposure to prions, the infectious protein that causes “mad cow disease,” according to a new case report.

According to a report published Wednesday (July 1) in the New England Journal of Medicine, the accident occurred in May 2010, when the technician, 24, was working in a prion research lab. She was working with samples of brain tissue from mice that had been infected with a form of mad cow disease, formally known as bovine spongiform encephalopathy (BSE).

While using forceps to handle the samples, she accidentally punctured her thumb through a pair of latex gloves, enough to break the skin and cause bleeding, the report said.

More than seven years later, in November 2017, the woman began experiencing “burning pain” in her neck and right shoulder, which later spread to the right side of her body. A year later, in November 2018, doctors checked her cerebrospinal fluid (CSF) sample and it looked normal. But by January 2019, she began experiencing symptoms of depression, anxiety, memory problems and visual hallucinations.In March, her CSF and blood samples tested positive for variant Creutzfeldt-Jakob disease (vCJD), a fatal brain disorder that can take years to manifest after exposure to the “mad cow disease” prion. The woman died in June 2019, 19 months after her symptoms first appeared.

Only a few hundred cases of vCJD have been reported, mostly linked to the consumption of contaminated beef (from cows infected with mad cow disease) in the UK in the 1980s and 1990s, as previously reported in Live Science. The disease is caused by abnormal folding of the prion protein, which causes lesions in the human brain. According to the Centers for Disease Control and Prevention, there is strong evidence that the prions that cause mad cow disease are also responsible for the outbreaks of vCJD in the UK in the 1980s and 1990s. (It should be noted that “classic” Creutzfeldt-Jakob disease is a related but separate disease from vCJD. Classic CJD was first diagnosed in 1920, can be inherited or occur sporadically, and is not associated with the consumption of contaminated beef).

Since the woman was born around the time the BSE cattle outbreak began, it is possible that she could have contracted vCJD by eating contaminated beef, but this is unlikely, report authors from Assistance Publique-H?pitaux de Paris, a public hospital system in Paris. vCJD, on average, after exposure to contaminated food, the report says It takes about 10 years to show up, and the last two vCJD patients in France and the UK died in 2013 and 2014, respectively.

So it’s possible that the woman got sick from exposure to laboratory material contaminated with prions. Studies on animals have shown that injection into the skin is an effective route of transmission for these prions.

A patient in Italy also developed vCJD after exposure to BSE-infected brain tissue in a laboratory setting and died in 2016, according to the report.

The authors conclude that “such cases highlight the need to prevent the transmission of variant CJD”, which can affect humans in the laboratory.

The report does not specify what safety measures were taken in the woman’s lab or how she was treated after initial exposure. However, in July 2019, AFP reported that the technician’s family filed a complaint against the National Institute of Agronomy, where the accident occurred, citing “manslaughter.” According to AFP, the complaint said the woman “did not receive risk training”, did not wear “adequate safety equipment”, and did not have follow-up medical care, according to the AFP report. The complaint says the woman in particular should have worn “cut-proof gloves” instead of latex gloves; and that the woman did not undergo decontamination procedures until “about 20 minutes” after the injury.INRA told AFP that it was working with health authorities to investigate the case and promised to maintain transparency.