Inspired by true events
The movie REC (2007) was inspired by a real case of a rabies outbreak. That's "inspired by" NOT "based on."
Back than I know this movie was taken pretty seriously as an actual event that happened and somehow got covered up.
*beep* with diseases like this happens all the time. The CDC is not going to announce to the public about an outbreak of something. Especially if they have it contained and no one really knows. Why would they want to cause panic unless they couldn't contain the virus? Its just like Aliens dude. The government is not going to expose that kind of stuff.
So whose not to say something similar like this happened somewhere?