The Biological Chernobyl

Last week, I had to re-take a ‘Biosafety and Biosecurity’ online course. At the institute where I am doing my PhD, it’s mandatory to re-take this course on a regular basis to make sure that all employees are well versed in keeping themselves, others, and the biological specimens they work with safe. This time (the fourth time) that I retook the course, one slide stood out to me in particular. It was a slide on the “Sverdlovsk Incident”.

On this slide, there was a figure taken from a 1994 scientific manuscript published in the highly respected journal Science. It was a map, with several different villages marked on it. The caption read, “villages with anthrax”. The take-home point of this slide was, “Humans can be a weak point in biosafety and biosecurity protocols”.

Looking at this map, I was reminded of maps of Chernobyl – perhaps spurred by the Soviet-sounding names of the indicated villages – that were shown during a tour of the site of the former nuclear power plant that I went on a few years back. These maps showed how the southeasterly wind had swept the infamous radioactive plume down towards Belarus, in a relatively straight line.

My boyfriend in front of the "USSR Eye of Sauron",

as our tour guide through the Chernobyl Exclusion Zone described it.

And indeed, I was not the only one to note that similarity – though Chernobyl occurred nearly a decade after the Sverdlovsk Incident of 1979.

Nonetheless, when anthrax cases first started popping up in the spring of 1979, the Soviet explanation for the cases was that the outbreak was natural. Soviet officials, doctors, and scientists asserted that the 96 humans that were infected had come into contact with the nasty bacterium after eating contaminated meat, or otherwise coming into contact with infected animals.

In general, it would indeed be possible for Bacillus anthracis, the bacterium that causes anthrax, to have popped up seemingly out of nowhere. Bacillus anthracis is especially sneaky in that it can survive for an impressively long time as a bacterial ‘spore’ – basically a mummified, hibernating version of itself. When in the form of a spore, bacteria like the one responsible for anthrax infections can survive for decades and in normally deadly conditions like drought. ‘Sporulating’, or becoming a spore, basically puts the bacterium’s life cycle on pause. But then, when conditions become more favourable again, that spore can ‘germinate’, meaning that the bacteria reanimates and becomes capable of infecting and replicating once more.

As a spore, Bacillus anthracis can survive in soil for a very long time, and indeed historical records showed that anthrax had naturally popped up in the Sverdlovskaya oblast before. The 2021 movie "The Power of the Dog" makes reference to this periodic popping up of anthrax, although it's set in Montana in the 1920s rather than the USSR. Side note - that appearance of anthrax is indeed historically and biologically accurate, as Montana too has a history of sporadic anthrax appearances.

However, international researchers wanted some hard data to back up the claim of a natural origin (sound familiar?), and eventually, after years of negotiation, a team of U.S. scientists was allowed to visit the scene of the anthrax epidemic, and investigate its origin.

Matthew Meselson and his team of researchers who authored the 1994 manuscript that described those investigations were meticulous. They tracked down – as much as was possible, as some records had been destroyed – the human survivors and family of those who had died of anthrax, unearthed archives of anthrax cases in livestock in the region, and dug up meteorological data to see when the wind had been blowing southeast.

And eventually, what made Matthew Meselson and his team of researchers especially suspicious of an un-natural source of the 1979 anthrax outbreak was the striking straight line that the affected villages formed. A straight line pointing southeast, which from their 1990s vantage point must have looked strikingly similar to the southeasterly line of radioactivity that Chernobyl was by then famous for. And strikingly, the origin of that straight line of anthrax cases was unmistakably located near a military compound known as, in the typical flowery descriptiveness of the time, ‘Compound 19’.

Taken together, their data led them to “conclude that the outbreak resulted from the windborne spread of an aerosol of anthrax pathogen, that the source was at the military microbiology facility, and that the escape of pathogen occurred during the day on Monday, 2 April.” With 96 cases of human anthrax, this data established the “Sverdlovsk Incident” as the largest documented outbreak of human inhalation anthrax.

Decades later, it came to light that indeed, humans had been the weak point in this outbreak. Local sources would later on describe that routine maintenance had been performed at the Soviet Ministry of Defense’s Scientific Research Institute of Microbiology spore production facility, which was housed in - you guessed it - Compound 19. The current consensus on what happened is that the safety air filters of the facility were compromised during this maintenance.

Two broad themes from this story stuck out to me. The first was that, as my institute’s course in biosafety and biosecurity pointed out, humans are often a weak point in these matters. In fact, the same was true in Chernobyl. The famous nuclear explosion also occurred during routine maintenance, when operators went against protocol and turned off vital safety regulations while doing systems tests. That’s why it’s extra important that in high-security labs like the ones I work in, people have to be calm, alert, and comfortable to ask their colleagues for advice if something seems to be going sideways. More minds are better than one in problem solving. Personally, I also cite it as a reason for always entering the lab only after I'm fully caffeinated - and thereby fully alert.

The second theme was that it took an independent team of scientific researchers to discover the truth about what happened. This speaks for the societal importance of we scientists – and for international collaboration and openness. It’s a tricky theme to this day, but an important one nonetheless.

Until next time –

Maybe treat your own friendly neighbourhood scientist to a coffee, in the name of biosafety and biosecurity ;)

~ Alex

P.S. If you'd like to support the caffeination of this particular scientist, you can always do that via Patreon!