Feels oddly allegorical, if one is so minded. Otherwise a pretty effective, straight Crichton-eqsue sci-fi thing.

I was going to say the same thing, about it being an allegory for something.

Such simplicity.. the door was open.. the infection mutated, but is usually weaker.. no need to panic.
I would hope there IS reason to panic.

Works both literally and (as a couple of people mentioned above) allegorically.