‘World War Z’ Will Veer From the Novel

The film adaptation of Max Brooks' popular novel World War Z: An Oral History of the Zombie War has a release date and a plot synopsis. The film will compete (as it stands) with Disney's Lone Ranger among others on December 21, 2012. More surprisingly, however, is that the plot will differ drastically from the novel.

Here's Wikipedia's summary of the book:

"World War Z is a collection of individual accounts in the form of first-person anecdote. Brooks plays the role of an agent of the United Nations Postwar Commission who published the report a decade after the Zombie War. The United Nations left out much of his work from the official report, choosing to focus on facts and figures from the war rather than the individual stories that form the bulk of Brooks' novel. The interviews chart a decade-long war against zombies from the view point of many different people of various nationalities. The personal accounts also describe the changing religious, geo-political, and environmental aftermath of the Zombie War." 

With that documentary/memoir-like description, it would make sense for the film to take some liberties, but it appears to have emptied the liberty vault:

"The story revolves around United Nations employee Gerry Lane (Pitt), who traverses the world in a race against time to stop the Zombie pandemic that is toppling armies and governments and threatening to decimate humanity itself.  Enos plays Gerry’s wife Karen Lane; Kertesz is his comrade in arms, Segen." 


It could be careless writing, but it sounds like Brad Pitt is fighting a "Zombie pandemic" as it's happening, whereas the book has a reflective tone dealing with the aftermath.

For those who've read the book, does the film appear to have gone too far in making changes?

For those indifferent to the source material, World War Z stars Pitt with Bryan Cranston, James Badge Dale (The Pacific) and Mireille Enos (Big Love). Marc Forster (Quantum of Solace) directs with the heavily changed script by Matthew Michael Carnahan (State of Play) and J. Michael Straczynski (Thor).