Trixie Disaster

Beginning
The disaster takes place in undisclosed time, presumably in 2010. It starts after a plane carrying a rhabdovirdae prototype bioweapon called Trixie crashes in a creek near Ogden Marsh. The virus begins taking its effect after a few townspeople drink the contaminated water starting with Rory. Around 25 hours after the disaster, the U.S. militaryarrive in hazmat suits and gasmaks, and swarm the streets of Ogden Marsh, initiating a quarantine.

Containment
The military,around two hours afters arriving, managed to round up almost all Ogden's residents, and put them under quick oppression by screening for the virus. After the military finished with weeding out the "Crazies," they shipped healthy non-infected citizens to a safe area outside the quarantine zone. Citizens were equiped with medical braclets for tracking and identification purposes.

Failure and Cleanup
Around six hours after the military's arrival, the quarantine failed causing a breach into the high school. The military, 15 minutes after the breach, evacuated in helicopters and left. They left infected and non-infected citizens strapped to gurney's within the high school. The infected and non-infected that were in the camp managed to re-enter Ogden Marsh. Two hours after the high school quarantine failure, the military was ordered back into Ogden Marsh to shoot anyone on sight. In this case, to clean up the failure of the high school breach. As far as the viewer is aware, there is no evidence that this order affected the citizens already evacuated by bus or cattle truck. However, sometime later the protagonists discover trucks containing bodies of the people who had been approved for evacuation, suggesting that the government had them executed either to ensure that no infected slipped through the cracks or to keep any information about the event getting out.

Cover-up
The military eventually began withdrawing from Odgen Marsh when an order came in to use a bomb to destroy the town. The goverment covered up the bombing, saying that a chemical plant exploded, which also blew up the truck stop.

Fate of Survivors (Theory Zone)
The main characters will eventually make it to Cedar Rapids, which, based on the satellite at the end of the movie, shows it's the next town to be contained. However, this is because the Trixie Virus managed to get to Cedar Rapids, thus not being contained as the government would have hoped. The movie implies that not many people escaped Ogden Marsh alive, but based on the amount of residents in Ogden Marsh, we might assume at least 200 non-infected residents escaped [conjecture]. Near the end of the movie around 4 to 5 cattle trucks are shown that were originally supposed to carry the non-infected to safety. However, you find out that those people were executed by the military, although the actual order to kill those residents was never seen in the film. Based on the timeline, we can assume the order was within 12 hours of the military's arrival.

Since the film takes place over three days and two nights, we might assume that the military, before those orders, evacuated the residents far from the blast radius of the nuclear device, likely to Cedar Rapids where the military could house them and keep them safe. (That's a theory that hasn't been proven; the ending just showing dead innocent people in one truck burned to a crisp. However, it might explain why we only see 4 to 5 trucks of dead people, instead of many more.) The end of the film suggested that the government was covering up the incident, in which creates a theory that they would kill any person who knew about what was going on. An alternative theory is that one of the citizens on those cattle trucks were infected, causing the military to shoot the innocent who weren't infected.

There were more residents in the rescue zone who were waiting to get evacuated, which is what leaves the possibility that not everyone was killed; however, we don't actually know whether there were any other survivors since it was not shown or stated in the film. The movie leaves it open to anyone's guess. The movie leaves out key details about the military, as opposed to the 1973 film. The 2010 movie conveys that the Army and government are a machine that will stop at nothing to achieve their goal. This is correlates with the 1973 version of The Crazies, whose message was conveyed during the Vietnam War as "the military is just as bad as the crazies, if not worse."