2004-09-27 04:24:35 UTC
salt! Interesting article from today's Toronto Star:
"The retreat of glaciers around the world is the most visible - and
depressing - sign of global warming.
If that retreat continues at its present rate, it won't be long before the
glaciers will be gone, and the world of biology in the Arctic and high
altitudes changed dramatically.
So far, our attention has been focused on the extinction (or arrival) of
plants and animals, but are we in danger ourselves?
A team of scientists writing in the journal Medical Hypotheses claims that
the world's glaciers and ice caps are loaded with infectious agents,
especially viruses, and that their release by melting poses a new medical
Could they be right?
Here is what they say: Viruses of many kinds - including influenza - can be
frozen solid and still be infectious when they're thawed, so storage in ice
is not necessarily destructive.
A second point is that there's no reason to think that being frozen for
50,000 years is any worse than being frozen for five.
Of course, you have to get the viruses into the ice in the first place - and
then get them out, fully infective - if they're going to be a threat.
How would that happen? The authors point out that the life cycles of certain
viruses suit them to this kind of scenario.
One is polio. The feces of infected people are full of polio viruses, and
these often find their way into local rivers or streams, eventually reaching
The virus also freezes well.
No one has a clue whether or not it's found in ice, but the authors
nonetheless contend that "ice has a high potential for being a reservoir for
The same is said for influenza.
In this case, the virus moves long distances, usually in the guts of
migrating wild ducks.
That implies that Arctic ponds and streams might be loaded with live
influenza viruses every summer. They could survive for days in water, and
for who knows how long in ice.
Direct evidence for polio or influenza viruses actually being locked in the
ice, ready to be unleashed by melting, is pretty scant. It amounts to
educated guessing. There is a better case for a less-well-known group called
They are odd: For one thing they prefer ocean fish (that's actually their
so-called reservoir), but will happily infect mammals, including us.
They are responsible for causing disease in an incredible variety of organs
(everything from the liver to the brain) in an equally diverse group of
mammals, from rabbits to grey whales.
The whale is an intriguing example.
Grey whales, which are full of Caliciviruses, take part in a famous annual
migration along the California coast and they encounter sea lions and fur
seals along the way, both of which are Calicivirus carriers themselves.
There's lots of opportunity for loose viruses to find their way into Arctic
waters, in which they survive very well.
And they might, just might, get splashed onto a glacier and locked into the
This theory argues that some viruses might emerge from the ice only after a
very long time.
In 2002, a Calicivirus isolated from an Alaskan Steller sea lion was found
to be genetically identical to a virus discovered more than 50 years ago.
That virus has a weird history: It was first identified in 1948, then
vanished, was rediscovered in 1968, then vanished again, only to reappear in
There appears to be neither rhyme nor reason to that cycle, but you could
speculate (as the authors do) that each appearance points to a single huge
release of viruses from the ice.
We know polio and influenza are very dangerous for us. It's not so crystal
clear with Caliciviruses. Animal biologists who have had contact with
infected sea lions and fur seals have become ill, though not seriously.
There's also suggestive evidence of slightly higher rates of Calicivirus
infection in some people with hepatitis and higher rates of abortion in
But the medical picture certainly isn't stark as it is with those other
So, should we be worried? At the moment it is far from being an airtight
Medical Hypotheses, which published the report, floats many, many ideas that
never again see the light of day.
But this one has, if not the ring of truth, at least a hint of it"