REC (2007)

A TV crew doing a documentary piece on Firefighters goes out with the team on a call to an apartment building where an old lady is acting strange.  When the policemen and firemen try to help her, she attacks them, biting one of them in the process.

When they attempt to get help for their injured co-worker, they find  the building has been sealed off and authorities outside announce that they are quarantined.  A health inspector is sent in to test those in the building to see who is infected.  The virus, which is spread via saliva, was detected by the Vets office when a tenant brought in their dog.

This is shot from the cameraman's point of view which keeps the viewer right in the middle of things, rather than as an observer.  The movie is much better than the US version, Quarantine, which kept the cause of the outbreak hidden for most of the movie.  There are less plot holes.  Also the reporter is frantic but not as annoying as she doesn't screech and blubber throughout the last part of the film.