Cynthia Higginbotham [email removed] writes:
>From: [email removed] (Andy Lilly)
>
>> > First, viruses tend to be *very* species specific.
>
> *RABIES!* (Which afflicts *all* mammals with varying degrees of
> lethality, i.e., some frequently infected mammals have large
> populations of immune carriers....)
Mea culpa -- you caught me making an overly broad statement. Let me
try that line again:
"First, viruses *tend* to be very species specific."
Both influenza and rabies are examples of multi-species virii.
As far as I know, however, they are still both limited to class
Mammalia. Influenza is unstable genetically, which is why there
are so many flu strains and why coming up with effective vaccines
is so hard. Bubonic plague is caused by a bacterium, _Yersinia
pestis_ (unless they've changed their mind about the genus again),
so it's a slightly different story. Many non-viral microorganisms
could be expected to have effects in alien ecologies that are
chemically similar to our own, especially those involved in
decomposition. The bacteria and fungi work directly on the
chemical structure of an organism, giving them a lot of food
opportunities.
Viruses are another story. Typically, viruses have a "host range"
of organisms they can infect, and usually this range is limited
to one species. From what I recall, a virus targets it's quarry
based on the chemical antigens and structure of the surface of the
preferred cell. (So HIV attacks certain white-blood cells, but
not, for example, nerve cells.) So a virus will typically be
optimized to attack one specific sub-system, and sometimes the
optimization is very very specific. The viruses that attack
multiple species are usually targeting very similar cell types.
Furthermore, the target cell needs to be able to interact with
the DNA or RNA strand the virus releases. If the alien isn't
DNA/RNA based, or simply can't produce the parts the virus needs
for construction, the infection won't work.
There are usually subtle differences between cells even in similar
species, especially at the cell membrane level viruses use to
recognize potential targets.
Conceivably, a virus designed to affect all Terran mammals could
infect the vargr, since vargr are Terran mammals, and members of
a genus in class Mammalia related to _Canis_. But all external
similarities aside, a human should be more closely related
genetically to a strand of kelp than to an aslan, or any other
alien. (In Traveller this may not be true. But then, the aliens
in Traveller are more science-fantasy than reality, of course.)
Targeting specific species would be simpler. You just have to
pick a cell type unique to the population that you are targeting.
This sort of thing might make a horror like a disease that prefers
Vilani or Zhodani, for the most part, possible. You really
couldn't *trust* such a thing, since the human minor races are so
closely related, but someone might try.
I suppose one could speculate about the existence of a Lucanian
biowar weapon that did target several species, not necessarily a
virus, that mainly was meant to nail humans. That might have some
interesting effects on future history -- the former territory of
the Imperium might end up being dominated by a number of very
non-human alien species that were unaffected by the weapon and
thus lucked into ready-made pocket empires early on. Some of
the nastier may have even helped the weapon along....
Yuck. This is getting ugly. As far as I know, the Imperium
never used CBW, although they did stockpile some in the Marches
during the bitter Third Frontier War. The Second Empire of
Gashikan did mount a particularly despicable attempt at
xenocide in the -1400s (31st century AD) against the entire
vargr species, using a series of microbes. The vargr stopped
it, but almost all the vargr in Gashikan sector died. It was
the worst part of a long series of interspecies wars set off
by the Sack of Gashikan in -1658 (AD 2860). Note that only
the vargr were targeted. An Ancient biowar weapon seriously
depopulated Zhdant, but it was targeted primarily at the world's
(now extinct) Droyne population...and who knows *how* it worked;
it was an Ancients weapon. (Besides, it was out of character.
Not only did it not kill all the humans, it was misdelivered
and didn't hit right until after the Zhodani had space-flight.
Usually Ancient weapons seem to hit whatever they attacked, and
destroy whatever they hit.)
Steve Bonneville
[email removed]