

The US intelligence community had long suspected the Soviet scientists were working on anthrax as a biological weapon, so the news of an outbreak of the disease in April of 1979 certainly looked like an accidental weapon release. A total of 66 people died in the city of Sverdlovsk (now renamed Yekaterinburg) and many more fell ill. The Russians swore at the time this was a natural occurrence caused by sick cattle, and that story held up for years. Now, long after the true cause of the outbreak was revealed, scientists have been able to perform DNA analysis on the deadly bacterial strain.

News reports in 1979 frequently speculated that the deaths were a result of accidental or intentional infection of the population with a weaponized strain of anthrax. If the Soviets were good at anything, it was sticking to a story. Nearly a decade after the outbreak, a team of Russian scientists came to a conference in at the National Academy of Sciences to present evidence that the Sverdlovsk outbreak was merely the result of humans consuming meat from animals that had contracted anthrax. It’s not impossible—anthrax bacteria are found in soil, and animals do sometimes become infected — though no previous outbreak had ever killed so many people via this vector. 

The official explanation might have held up indefinitely if not for Harvard biologist Matthew Meselson, who led a team to investigate the outbreak in 1992, following the collapse of the Soviet Union. Soviet doctors had done autopsies on the victims of the outbreak, and it turns out those samples survived. The medical personnel in Sverdlovsk had hidden the original tissue samples in the local hospital’s pathology museum in order to prevent the KGB from confiscating them. From viewing the original materials, Meselson’s team knew without a doubt they were looking at inhalation anthrax, not ingestion anthrax as the Russians originally claimed. A former Soviet scientist later came forward to confirm the anthrax spores were released in 1979 due to a faulty air filter in the Sverdlovsk military installation.


Anthrax has been researched as a bioweapon not only because of its deadliness, but because the Bacillus anthracis bacterium forms spores (above). These are compact capsules bacteria generate to survive harsh conditions. It’s a bit like hibernation. When conditions improve, the spore germinates and becomes an active bacteria again. This makes anthrax very easy to transport and distribute as a weapon.DNA testing was still in its infancy in 1992 when the deception was uncovered, still everyone wondered if the Soviet anthrax strain was truly weaponized. Could an accidental release of unmodified anthrax kill dozens of people? Preliminary testing done in 1996 revealed little, but more recent testing on samples from Sverdlovsk allowed for a full analysis of the 1979 strain.

Microbiologist Paul Keim reports that the full sequence of Bacillus anthracis from Sverdlovsk is a very close match for unmodified anthrax strains. If the Sverdlovsk lab was trying to modify anthrax, they were not successful at it. It didn’t take a highly modified bioweapon to kill those 66 people, so how much worse could it have been with a weaponized strain?