Having poo-pooed the possibility of killer viruses roaring out of the tundra to kill as all – see here – I find myself having to reconsider my words. Just slightly, mind, but a reconsideration nonetheless.
This is because of an excellent post in Nature News recently, entitled “Infectious diseases: Smallpox watch“, by Sara Reardon. This has raised quite a stir in the Twittersphere, as people speculate on just how likely this is, but I think the article itself does a very good job of discussing the possibility that smallpox could come back from the grave(s).
I have discussed smallpox a number of times in this blog, with one of the most read posts being this one by my PhD student (and now postdoc) Alta van Zyl. I recall a while back a discussion around just how likely it was that people working on expanding what was the Rietfontein Infectious Diseases Hospital (now Sizwe Hospital)’s premises in Johannesburg, would find live smallpox in coffins of people who died of it at the old Hospital and were buried nearby.
The verdict then was “No” – Johannesburg is too hot, and the was seen to be NO chance of the virus surviving the rapid putrefaction that occurs in these parts.
Sara Reardon’s essay, however, raises the real, if rather remote, prospect of there being live smallpox in mummified corpses which have either dried out at low temperatures, or been frozen soon after death, in permafrost. She says that
“A more likely source of infectious virus would be frozen bodies. Influenza viruses seem to be able to survive freezing in lakes and may thereby infect migrating birds…”
Now the good thing is that people have actually gone out looking for live virus in just such potential sources, and found nothing except fragments of DNA.
However, she also says:
“Another concern is that smallpox could escape from a secret cache. Few biosecurity specialists believe that the two stocks kept at the CDC and VECTOR are the only ones in existence. For instance, variola could very well be in the freezer of someone who defected from the Soviet Union…”
Now, the old Soviet Union had an active programme on weaponising smallpox, with some sources claiming than “several tonnes” of material were eventually made. There is even evidence that smallpox escaped from a facility in Aralsk, Kazakhstan, in 1971. What is not so clear is where any of this material is NOW, and in what state it is.
Time to work on the emergency-response smallpox vaccines and strategies, folks – even if you use the potential threat of monkeypox as the reason!