Over the past several weeks my inbox has featured ProMED reports of an anthrax outbreak in Siberia, and the story has been growing increasingly curious. The source of the human cases has been presumptively identified as an infected reindeer… that died roughly 80 years ago. That’s odd, even as disease outbreak stories go. The reindeer was frozen in permafrost (i.e., top soil that is frozen solid, and as it turns out, is an excellent preservative), and the permafrost in Siberia has been melting at higher rates than usual this summer. The long-dead reindeer surfaced from the no-longer-frozen ground during a heat wave, and… the rest is history. As it turns out, there are also numerous mass cattle graves from anthrax outbreaks in Siberia, and it is therefore highly possible that this may happen again in the not-too-distant future. This would just be a curiosity and a reason to issue a local warning were it not for a few more, shall we say interesting, finds when investigators looked at the Siberian permafrost and its surrounding landscape a little more closely.
During permafrost melt, water is leeched into nearby bodies. One such instance is along the banks of the Kolyma River, and this is where the truly bizarre twist on this story -and its very real implications- comes in. This region of Siberia suffered a smallpox epidemic in 1890, and a large chunk of the residents perished. The bodies were buried at a single site along the river bank in the top layer of soil, which has been existing as permafrost for most of the intervening time. This summer has called that into question. The melting permafrost has caused a rise in the Kolyma River level, and the banks are eroding away. Investigators from the Virology and Biotechnology Centre (known colloquially as VECTOR) in Novosibirsk explored the situation, and were able to examine some corpses from the burial site that were so well-preserved that they had identifiable lesions (“pox”). Material from these lesions was tested and, lo and behold, contained detectable levels of Variola virus (smallpox) DNA. Things get a bit hazy here, as I am not clear as to whether the group tried to isolate live virus from the corpses and failed, tried and succeeded but do not want it publicized, or did not try at all. Nevertheless, this is absolutely astonishing and truly unexpected.
This is where things stop getting curious and amusing, and start raising an uncomfortable specter: bioterrorism. While anthrax is widely considered a potential bioterrorism agent, it does still occur naturally in many parts of the world. Seeing anthrax cases does not make one immediately jump to the “BT” conclusion (New York City incident notwithstanding). Smallpox, however? That’s a whole different animal. Smallpox was eradicated from the human population as of 1977, and there has not been a case since. The last remaining virus stocks are in the custody of two entities: the United States Government and the Russian Government, and this arrangement was awkwardly brokered during the Cold War. It is generally accepted that any cases of smallpox observed that were not laboratory-acquired would indicate an intentional attack. I told my class that very sentiment two weeks ago phrased as something like: “if you ever see a smallpox patient, something very, very bad is going on in the world”, and gave it a diagnostic flag of “political unrest/instability”. This finding calls that entire premise into question, but imagine for a moment that you turned on the news and learned about a smallpox outbreak. What would your immediate conclusion be? What if the outbreak occurred in Russia (as it most likely would, if this mechanism was the source), and you were a Russian citizen learning about it, what would your first thought be? We’ve been attacked. In actuality we may have just spoken too soon about smallpox being eradicated, because frankly, who would have thought? Fortunately any outbreaks would be quickly stamped out with a rapid ring vaccination campaign and so I don’t fear the disease in the least. What I fear is an alarmed response to what is an unexpected and rather wacky natural occurrence.
[NOTE: the Smallpox Bioterrorism Guide is published by PM Medical Health News]