Okay, well there goes any chances of not posting any spoilers.
Anyway, I can very definitely argue that the approach was not scientifically sound. Now, you have to understand me to understand how I critique movies. First, classification:
1. Comedy
2. Science Fiction
3. Fantasy
4. Boring
Now, if it's boring, I don't care.
If it's Fantasy, I don't care.
If it's comedy, I don't care.
If it's Science Fiction though, it better be more scientifically sound than the theory of gravity if I'm going to find it intriguing.
Now, the thing about disease strand mutation is that genetics mutate one step at a time. The first step would be for it to become an airborne strand of rabies. This would infect all the animals in the building, they'd go crazy, then they'd all die, either through euthenasia or by the disease, because rabies does kill the host, which is why it's not a realistic threat. The second step, which wouldn't happen because all of the hosts would already be dead, and so would the virus, would be for the effects of aggression, rapid salivation, and light sensitivity to begin effecting humans similarly to how it effects animals. The third step in the mutation process, which, again, wouldn't occur because rabies kills too quickly to mutate extensively, would be for the disease to incur traits that would cause the host to develop ignorance to physical harm, increased physical strength, and reduced social rationalization.
A few other things that weren't considered:
1. A rabid animal in the wild is quite a bit weaker than a healthy animal in the wild. The disease decrepifies the host. Likewise, a strand which mutates to infect humans in the same way would cause those humans to be sluggish, weak, and jumpy.
2. Rabies does not cause the infected to go hunt down prey. It causes them to become aggressive and easily startled. Basically, the infected would not become flesh-eating zombies; they would just become lethargic and unpredictable.
3. The old lady wouldn't have been sitting on her couch staring at her TV; she would have been tweaking out in a corner. And the dog? She would have been constantly under the impression that the dog was trying to kill her, and would thus be lashing out at it, and it probably would have just killed her because it was a big freaking dog.
Again, I'm very critical of science fiction. Now, had this movie not made any attempt at having an explanation, or had just said it was a biological weapon (it did hint at this notion near the end of the movie, but it still didn't try to explain the infection this way; it just threw it out there to give conspiracy theorists another thing to lie awake at night being fearful of), I would just have said, "okay, whatever, another zombie movie with a retarded ending because they ran out of good deaths...before anyone even died." But instead they tried to make it seem realistic, which ruined it IMO.
