In the spring of 1979, the Soviet city of Sverdlovsk was covered in a disastrous plume of anthrax spores. The leak came from a secret bioweapons facility that produced anthrax on an industrial scale.
The anthrax spores spread at least 50 kilometers from the research complex and killed about 100 people. It was covered up by the Soviet government for years because they were in violation of international agreement to ban offensive bioweapons research.
Now, researchers have found samples from that anthrax leak and tested it with modern high-throughput whole genome sequences and uncovered tantalizing genomic clues into that bioweapons research.
What is anthrax?
Anthrax is a disease that can cause black ulcers on the skin, stomach pains, fever, vomiting, and potentially kill infected people. It is caused by the bacteria Bacillus anthracis that can be found in soil all over the world and sometimes infect animals such as cows and sheep. Humans can become sick if they came into contact with infected animals or animal products, but it generally does not spread between humans. Out in nature, the bacteria that causes anthrax can create spores, which are hardened structure that works as a resting state for bacteria until the conditions outside improve. When humans get exposed to anthrax spores, the bacteria starts to grow and multiply, eventually producing toxins and causing illness. Humans can get exposed through the skin, through breathing, through the gut or from injection.
What are bioweapons?
A bioweapon, or biological weapon of mass destruction, is usually a human pathogen that can be grown in bulk, stockpiled and used against human targets in warfare. Because the microorganisms that cause harmful and deadly human infectious diseases are not visible to most humans in the same way that many conventional weapons are, it adds an additional level of fear to the mix. There is also a specific time period between the time the bioweapon is deployed and people become infected until symptoms start to appear (called incubation time), the perpetrators can escape unnoticed if the security services are not on top of their game.
Bioweapons can be made by isolating and growing harmful human pathogens and making stockpiles ready to be used, but there is an even darker side to bioweapons. It is that they can be genetically modified by adding in extra genetic material that makes them more durable, provide additional virulence or become resistant to antibiotics. The fact that anthrax can make spores make them resistant to the environment and can be spread as aerosols.
Anthrax was most recently used as a bioweapon during the 2001 anthrax attacks (also known as Amerithrax) where several letters containing Anthrax spores were sent to different people around the United States, killing five people and harming 17 others. The FBI suspected Bruce Edwards Ivins, a researcher at a lab working on defense against biological weapons at Fort Detrick in Maryland. He later committed suicide and the FBI investigation has been strongly criticized in a report by the National Academy of Sciences because the investigation was lacking in scientific merits.
Inside the Soviet bioweapons program
The Soviet biological weapons program out of the Biopreparat agency engaged in research and production of weaponized forms of dangerous human pathogens such as smallpox and anthrax. Because the Soviet Union had signed the Biological Weapons Convention (1972) that banned research into the offensive use of bioweapons, this research constituted a breach of that convention. Due to political pressure from the U. S and U. K, the Soviets agreed to inspections in the early 90s, but they were largely met with cleaned up facilities and denial from official sources.
One crucial event that occurred during the Soviet biological weapons program happened in the spring of 1979 at the city of Yekaterinburg (then called Sverdlovsk). Although covered up by the Soviet government for years, it was a research laboratory that worked on producing anthrax for as an offensive bioweapon. The event involved an accidental leak of a plume of anthrax spores from the facility that, together with poor emergency management, lead to the deaths of about 100 people (some at least 4 kilometers from the building complex).
What did the scientists uncover about the Sverdlovsk anthrax release?
Historical information about this event, as well as results conclusion from genomic research on those anthrax samples are discussed in the paper A Bacillus anthracis Genome Sequence from the Sverdlovsk 1979 Autopsy Specimens written by Sahl and colleagues and published in the journal mBio in 2016.
Apparently, the leak resulted of failed maintenance of safety air at a spore production facility called Compound 19. Confirmed anthrax cases were thought to extend several kilometers for humans and about 50 kilometers from farm animals. Early PCR analysis confirmed anthrax and some samples from human autopsies were fixed with formalin and stored.
Now, these researchers leveraged high-throughput genome sequencing tools to get a good draft genome of the anthrax strain that infected these victims. Their phylogenetic analysis placed it among other Asian strains and there was no evidence of genetic engineering or selection experiments to breed antibiotic resistance.
What can this research lead to?
There are several beneficial consequences of this research project.
First, it will facilitate the collection of high-resolution strains of B. anthracis. Strain collections are the bread and butter of microbial research, because it provides a common standard that allows different researchers from all over the world to ensure that they work on the same thing and that the knowledge they gain are widely applicable. Together, scientists can build a much larger knowledge base than they could have done if there was no systematic strain collection available.
Second, it will help to understand and track future anthrax outbreaks. Because the researchers have a protocol that they used that work, it is much easier for other researchers to use this protocol as well instead of constantly trying to reinvent the wheel. The knowledge gained from this project will also inform future isolation and sequencing efforts.
Third, it will boost the ability to forensically track these anthrax strains in the context of bioweapon proliferation and tracking. In other words, if or when another anthrax attack happens, researchers will have a much better shot at tracking the source of those anthrax strains and potentially even increase the chance of identifying a perpetrator.
There is also another benefit to this research, which is that it provides additional information about what was going on at that bioweapons facility during the 1970s.