April 16, 2014 -- A French lab has lost more than 2,000 vials containing fragments of the deadly SARS virus, which killed nearly 800 people in a 2003 epidemic across four continents.

The Pasteur Institute in Paris, France announced this week that it realized it was missing the vials and contacted the country’s National Security Agency of Medicines and Health Products to conduct an investigation on April 8, according to a news release.

Although the fragments are not dangerous, they do raise concerns by revealing the lab’s vulnerability, said Dr. William Schaffner, chair of preventive medicine at Vanderbilt University Medical Center in Nashville, Tenn.

"It’s actually not in itself so scary but you wonder about the procedures in that laboratory,” said Schaffner, who is also a former president of the National Foundation for Infectious Diseases. “Could that lab and perhaps others actually misplace vials that have the complete virus so that it might escape?”

Read about the deadly virus that escaped from a Texas biolab last year.

SARS, which stands for severe acute respiratory syndrome, sickened more than 8,000 people a decade ago, and as researchers started to study it, some of them acquired the illness, Schaffner said. That was when they realized they needed to be more careful with it.

There have been no reported cases since 2004, according to the Centers for Disease Control and Prevention.

In the United States, SARS as a whole virus is considered a “select agent,” meaning it has the “potential to pose a severe threat to both human and animal health, to plant health, or to animal and plant products,” according to CDC.

Its symptoms start out seeming like the flu with a fever and chills, but within a week they progress to a higher fever, a dry cough and shortness of breath, according to Mayo Clinic.

The virus is believed to have originated in Chinese horseshoe bats in 2002 before spreading to cats sold at animal markets for food, and then spreading to humans. The outbreak in Hong Kong brought it to global attention, and it spread to two dozen countries, according to the CDC.

Schaffner said the virus fragments were likely stored in a lab refrigerator and forgotten about until the lab did inventory. He said the best case scenario is that they were accidentally incinerated and destroyed. The worst case scenario is that we will never know what happened to them.

“It reminds us that each and every lab must have rigorous safety procedures,” Schaffner said. “People must be trained, and there has to be good supervision.”

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