It starts with a black screen and the sound of a cough, humble and ordinary. From the ultimate in mundane health hiccups, Contagion builds relentlessly toward a frighteningly real speculation about what might happen if the next Swine Flu goes wide.

Steven Soderbergh's gripping new doomsday thriller doesn't play like science fiction because the director grounds the escalating action -- or inaction -- in actual epidemiology as practiced by Atlanta's Centers for Disease Control and Prevention and the Switzerland-based World Health Organization. Public health officials (Kate Winslet, Laurence Fishburne, Marion Cotillard and Jennifer Ehle) function as flawed tragic heroes as they try to figure out why the hell people are dropping dead in Hong Kong, Minnesota, San Francisco and beyond.

While the scientists track the outbreaks and search for a vaccine, ordinary civilians (Matt Damon, Gwyneth Paltrow) and a shrewd investigative blogger (Jude Law) imperfectly adjust to quarantines, riots and an overriding sense of helplessness.

Despite its fatal disease theme, Contagion https://contagionmovie.warnerbros.com/index.html, in theaters Friday, expends most of its dramatic firepower on the living, not the dying. Victims cough, turn pale, sweat, faint drool, and die. That's it.

By downplaying the death throes, Soderbergh and screenplay writer Scott Z. Burns have created arguably the most realistic in a long line of infectious thrillers that tap into the universal fear of random viral violence.

Most sci-fi and horror filmmakers exercise considerably less restraint.

For a refresher course in hideous fictional infections from the annals of sci-fi and horror film history, click through the Great Moments in Viral Cinema gallery above.

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Point of origin: 2011 Hollywood think piece.

Culprit: Jennifer Ehle plays Dr. Ally Hextall, one of the doctors who tracks the source of a global epidemic to a mysterious new virus that mutated in Asia.

Death throes: Coughing, followed by clammy skin, twitching, and foaming at the mouth.