Habitat Contamination

>But is there a need to import viruses, molds, etc that >are pathogens?
>Consider Fusarium head blight which >affects wheat, barley and oats and
>produce mycotoxins >such as deoxynivalenol (DON), also know as vomitoxin.
> >Why not screen it out from the seeds we import from
>earth? At the same time, import beneficial molds, those >needed for
>penicillin, those needed for making cheeses, >those needed for wines, for
>agriculture, for human >health.

Public health officials and engineers have faced some of these questions
before, e.g. in designing clean rooms for computer chip manufacture, low
contamination microbiology labs, etc.

But folks on this site are confusing two different approaches to pathogen
reduction, and I think the distinction is important to make.

Do we:

1) Make a "hit list" of the 100 or 1000 or 10,000 pathogens we're going to
specifically target for exclusion (Fusarium mold, measles virus,
Mycobacterium tuberculosis, Stachybotrys atra mold, poison ivy, etc.),
figure out precisely what it would take to eliminate those villians from the
seeds, seedlings, people, animals, materials, gases and soils brought up
from earth, and do it.

Or do we:

2) Aim for a low- to no-microbes policy, using broad measures like
irradiation of inaminate objects, lengthy antibiotics regimens and other
harsh (even dangerous) measures to remove microbes from colonists and other
living things, long quarantine periods, and potentially much more costly
in-situ generation of most of the colony's needs. By this last point I mean
the creation of water, atmosphere gases and soils from presumably sterile
sources like lunar regolith, crushed asteroids, etc., thereby reducing the
number of (possibly contaminated) things brought up from Terra.

The first alternative, targeted exclusion, is more easily done, depending on
what's on your hit list. It is already practiced here on earth (e.g. to
transport horses across state lines in the US you have to have a statement
from your veterinarian about the absence of certain diseases). But some
authors on this site seem to be leaning toward alternative #2. The No
Microbes position may seem more desirable to folks because of it utopian
simplicity. But I've tried to point out that we here on Earth live in a
complex milieu of microbes, so beneficial, some pathogenic, but most not
clearly in either camp. The arguments against the No Microbes position are:

1) These Middle Ground microbes (neither commensals nor pathogens) are
poorly studied and understood, and it might take decades to even figure out
how to exclude them. There are no broad-spectrum anti-virals or anti-mold
drugs, and spores (which most molds produce) are incredibly tough.

2) Steps to eradicate pathogens and Middle Ground microbes would almost
certainly wipe out commensals too. Your doctor will tell you that long-term
broad spectrum antibiotic use is a bad idea, because it alters your internal
ecosystem, killing the commensal bacteria that protect you. Reestablishing
that internal balance is not well understood.

3) The Middle Ground microbes may play roles in our ecosystem that we don't
understand. Some extreme Green Party types consider this blind spot in our
knowledge of the ecosystem to be sufficient reason for radically reducing
the technology level we currently employ. At the very least it deserves
considerable attention in the research leading up to the first orbital
colonies.

4) There may be an important role for some of the microbes on the hit list.
The much maligned structural molds that have received so much bad press in
the US for growing in people's homes and making them sick are, in the global
context, very important for the breakdown of decaying plant materials,
especially dead trees.

Here again I've taken 1000 words to say what somebody else might say in
less, so I'll stop now.

Brad W.