The beaver is a proud and noble animal

The last remaining strains of smallpox are kept in highly protected government laboratories in Russia and at the Centers for Disease Control in Atlanta. And, apparently, in a dusty cardboard box in an old storage room in Maryland. The CDC said today that government workers had found six freeze-dried vials of the Variola virus, which causes smallpox, in a storage room at the National Institutes of Health in Bethesda, Maryland last week. Each test tube had a label on it that said “variola,” which was a tip-off, but the agency did genetic testing to confirm that the viruses were, in fact, smallpox.

According to the agency, the virus was freeze dried and sealed in melted glass and the samples have been in storage since the 1950s. Smallpox can be deadly even after it is freeze-dried, but the virus usually has to be kept cold to remain alive and dangerous. The Food and Drug Administration had been using the building where the samples were found since 1972, six years before smallpox killed its last person.

“The vials appear to date from the 1950s. Upon discovery, the vials were immediately secured in a CDC registered select agent containment laboratory in Bethesda,” Benjamin Haynes, a CDC spokesperson, said. “There is no evidence that any of the vials labeled Variola have been breached, and onsite biosafety personnel have not identified any infectious exposure risk to lab workers or the general public.”

Haynes said that the CDC did emergency genetic testing of the strains to confirm that they were smallpox. It’s currently doing further tests to determine whether the strains are still virulent, which could take up to two weeks. “After completion of this testing, the samples will be destroyed,” he said. He said the FBI is currently helping the CDC investigate how the original samples were prepared and why they were stored in the building.

“The laboratory was among those transferred from NIH to the FDA in 1972, along with the responsibility for regulating biologic products,” Haynes said. “The FDA has operated laboratories located on the NIH campus since that time. Scientists discovered the vials while preparing for the laboratory’s move to the FDA’s main campus.”

If you’re not sure why this is such a big deal, it’s because smallpox killed some 300 million people in the 20th century alone, and is the only human infectious disease that has ever been eradicated—a process that took the greater part of the 19th and 20th centuries. WHO declared smallpox eradicated back in 1979, but two strains of the virus are kept for further testing in extremely secure labs in Atlanta and in Russia.

Those strains were supposed to be destroyed multiple times—first in 1993 and then in 1999. But researchers in both Russia and the United States wanted to hold onto the virus to continue researching it. Kathleen Sebelius, secretary of the US Department of Health and Human Services, said that keeping the virus was important because there could be unknown stocks of the virus out there somewhere. Little did she know, some of those stocks happened to be in a government building:

“Although keeping the samples may carry a minuscule risk, both the United States and Russia believe the dangers of destroying them now are far greater,” she wrote in a New York Times op-ed in 2011. “It is quite possible that undisclosed or forgotten stocks exist.

It was the second recent incident in which a government health agency appeared to have mishandled a highly dangerous germ. Last month, a laboratory safety lapse at the CDC in Atlanta led the agency to give scores of employees antibiotics as a precaution against anthrax.

In at least one other such episode, vials of smallpox were found at the bottom of a freezer in an Eastern European country in the 1990s, according to Dr. David Heymann, a former World Health Organization official who is now a professor at the London School of Hygiene and Tropical Medicine. Heymann said it is difficult to say whether there might be other forgotten vials of smallpox out there. He said that when smallpox samples were consolidated for destruction, requests were made to ministers of health to collect all vials. “As far as I know, there was never a confirmation they had checked in with all groups who could have had the virus,” he said.