This weekend, the virus disaster film "Contagion" was the top-grossing new movie in box offices across America. The film stars a heavy-hitting cast of well-known actors, including Matt Damon, Kate Winslet, Jude Law, and Gwyneth Paltrow. It's unsettling to watch for many people, because it's about a global pandemic of a deadly virus, which threatens to end civilization as we know it – which prompts the question: could this really happen? Dr. Jon Epstein  is a veterinary epidemiologist who specializes in emerging viruses, including Nipah, which was the inspiration for the virus in the film "Contagion."  Dr. Epstein is also associate vice president of Ecohealth Alliance.   Here's the trailer for "Contagion":