I seem to remember that when the first samples of moon rock were brought back to earth there was a lot of care taken with quarantine just in case there were any interstellar "nasties" therein.
Given that comets used to be blamed for outbreaks of plague and suchlike I wonder why there is no mention of similar precautions being taken with the comet dust samples.
Scientists were confident that high temperature sterilisation would kill all possible pathogens until the discovery of a new class of "prions" responsible for mad cow disease.
And just when I was running out of things to be worried about.........
Keef