Posts Tagged infectious disease

“Viruses” In The Environment

Over the past few weeks or so, I’ve noticed on Facebook several posts about how climate change has caused warming in the northern parts of the Earth, especially in northern Canada and Siberia.  The posts give information about how carcasses of dead animals (and, possibly, humans) are being exposed for the first time in ten, twenty, thirty, or forty thousand years (or even more) because the permafrost in that area is melting.  Potentially, many of those animals or humans died of infectious diseases such as anthrax, plague, or other highly communicable diseases, and the threat to us humans today is that a new outbreak could be started if we exhume the bodies without taking careful precautions to prevent spread.  They even give an example of an anthrax outbreak in Russia when an infected animal carcass was exhumed.  I fully agree.

I have two real comments to make about these stories.  Both points are short and simple, because I don’t have the space here to go into any detail about how to handle the exposed carcasses.  I’m not an expert in that, and there’s a lot of boring detail I’d have to list anyway.  My first point is that these stories are calling the agents that cause the diseases that could be exposed as being caused by “viruses,” even though the all the ones they list are actually caused by bacteria.  Viruses are not “bacteria.”  Viruses are submicroscopic organisms that cause disease, while bacteria are larger, and can be seen in a microscope.  I hope we will begin to use the two terms properly in order to avoid any confusion in the future.

Having said that, there are possible situations where real viruses might be uncovered by permafrost thawing (“permathawing”?)  I can conceive that sometime a carcass of a human who died of a virus disease (such as smallpox, influenza, polio, rabies, ebola, etc.) might be uncovered.  These are real viruses, not the “viruses” listed by the writers of the articles mentioned above.  Some of these might be dangerous.  But there’s a caveat, and this leads to the second point I want to make.

Viruses, on the whole, are easier to kill than bacteria.  It is true that both viruses and bacteria can be preserved for a long time by freezing.  A dead body, whether animal or human, which is frozen soon after death to a temperature well below zero (and it doesn’t matter whether we’re talking Fahrenheit or centigrade here; cold is cold) can preserve any infectious agent reasonably well.  But the agent will begin to die off as time goes by.  Bacteria will generally be preserved longer.  Viruses I suspect would become inactivated more easily.  But there are so many variables—how soon after death the body was frozen, how deep in the frost it was, what the temperature was throughout the frozen state, how long ago it died—that I can’t even begin to make generalizations.  For some viruses, like influenza, for example, I suspect that if a prehistoric human who died of a strain of flu as potent as the 1918 strain were exhumed, it might not be too infectious, since the flu virus can be destroyed relatively easily.  But I can’t be sure.  There is one virus I would be very suspicious of, were a human carcass infected with it were to be uncovered, and that is smallpox.  In lab studies, smallpox is more difficult to kill than most other viruses, and this could raise some serious issues.  The problem is made worse by the fact that we don’t immunize people against smallpox any more, and that means that any researchers under the age of about thirty or forty who might be working with recovered human remains from permathawing could be at risk for the disease.  Perhaps this is a good reason to bring back smallpox immunization, at least for people working in this area, if not the population at large.

In summary, let’s start using the terms “bacteria” and “viruses” correctly to avoid confusion in the future, and let’s be careful exhuming any dead carcass, human or animal.  Diseases have killed animals probably for as long as animals have existed, and those nasty “viruses,” potentially at least, could come back and do it again.  We might even uncover a virus we’ve never seen before.

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