Contamination:million year old organisms

Came across this article on reuters,here are a couple of quotes then the link

MOSCOW, March 3 (Reuters) - Hidden about four km (2.5 miles) beneath the ice near the South Pole lies a lake that scientists believe represents a lost world, harbouring organisms sealed off from the rest of the planet for millions of years.

Vostok has an added fascination for scientists because conditions there -- cold, with no light or air -- mirror those on Europa, one of Jupiter's moons where space probes have found evidence of an ocean below the frozen surface.
If living organisms are found in the lake, it could strengthen the argument for the presence of life beyond our planet.

www.alertnet.org...

My question is this, the scientists seem to be concerned about contaminating this pristine enviroment, should we also be concerned that the contamination may be reciprocal.Im not sure how this works ,im no scientist.Could there be microbes in this lake that could potentially cause unknown diseases etc.

Second question deals with the other part of the article re the similarities of the enviroment with that of europa.Should life(bacterial/microbial) be discovered in this lake is it a given that life will be found in similar enviroments through out the solar system.

Hope this is the correct place to post this thread(mods please move if not).
Any thoughts?

this is fasanating what life can go though and still thrive. while the thret of somethign down there harming us is almost unreal it is posable. the problem is virus are very specific a certin species a certin body part. and if it where a killer human virus it is doubtfull it would have lived this long with out a human host to multaply in and spread. most likely we will contamanate the hidden lake with our range of small organisms

It seems unlikely that there would be anything there that would be dangerous to humans, or any other surface lifeforms. Remember, bacteria and viruses evolve/adapt/thrive inside our bodies. The more people available to infect, the more likely a pathogen will evolve into a more deadly form. Since there are (presumably) no humans 4km under the ice, there's no place for pathogens to "hone their skills" so to speak.

I suspect they fear contamination of the underground lake with surface bacteria that might be able to reproduce under those conditions. If that happens, it might disturb a subtle ecosystem, or at the very least, make it more difficult to determine which bacteria have evolved in isolation vs. the newcomers.