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One thing that bugs me in sci-fi are alien diseases. It’s such a fundamentally flawed concept that, when used as a plot device, it disenfranchises me with the plot from then on. Given that I can get put off by as little as engine position on the models this isn’t saying much, but I’m going to list why you don’t need to worry about getting alien flu and dropping down dead in twenty minutes.

First, viruses. Now, I’m under the impression that most people don’t really understand what a virus actually does, so skip the next bit if you know. Basically, viruses penetrate a cell and insert their own genetic material into either the cell body or the DNA. This overrides the cell’s own code and hijacks the functions to produce more of the virus, and, as this is generally destructive to the host cell, it can be fatal if not checked by the immune system.

Generally it is assumed that our immune system has no defence against this, but while I do not deny that they will be not recognised as a pathogen (I’ll elaborate on this isn’t a problem in a moment), their method of reproduction will fundamentally not work on our cells and so the viruses effect will be mooted. Even if they use DNA/RNA[1] it is highly unlikely their codons will match, so, while their code says G-A-A-T-A-A- and they expect say… Lysine and Adenine[2]. Our cells would synthesise Glutamine and STOP, which would be utterly useless and wouldn’t form the necessary proteins.

For this reason alone, alien viruses would be utterly benign as they could not reproduce. A mutated strain also wouldn’t do anything as it would have to reorder its entire codon structure to function and I really can’t see a way that could happen in nature. Viruses struggle to pass between species, let alone between biospheres.

Bacteria are another matter, they would require a host species with similar internal chemistry to function as a pathogen, but that isn’t too much of a stretch if you’re in a universe where carbon and liquid water based life is common[3]. However, it seems illogical that humans will be incredibly susceptible to these micro organisms, in fact, given our immune system is pretty much geared towards identifying and eliminating foreign bodies (including the aforementioned viruses) it seems more likely that the bacteria will be susceptible to us. The bacteria are, after all, adapted to flummoxing a very different immune systems to our own and such a big species gap is unlikely to be surmounted by random evolution in our lifetimes.

Besides, even if we were successfully infected by a bacterium, the strain would have no resistance to the antibiotics we use and would actually be easier to treat than the stuff we’ve got now.

As it happens, the big worry would be our immune systems working far too well, and our ambassador having a severe allergic reaction and going into anaphylactic shock because of their ambassador’s detergent.

Join the discussion on the forum.

[1] Which almost certainly won’t be the case, but anything based on a different chemistry would be killed by your internal conditions anyway.

[2] Amino acids if you do not know.

[3] Just as an interesting note, any alien visitors to earth are more likely to catch a disease of a non-human species as they’d likely be a closer match to some other animal that us specifically.


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