Everything you touch in public has been touched countless times. Every drinking glass, faucet, doorknob, elevator button and light switch has been coated with the germs and fluids of strangers who've already handled an infinite number of other surfaces. If that's not good source material for a paranoia-inducing horror flick, what is?

Writer Scott Z. Burns and director Steven Soderbergh seize that theme in "Contagion" and deliver a grim look at humanity's response to the worldwide epidemic of an unknown disease. Though the movie shortchanges us emotionally, it delivers a credible, disheartening picture of greed and panic.

The film needed to run twice as long as its 105 minutes - in other words, as a four-hour miniseries with commercial breaks - to get us to care about the husband who loses his wife, the doctor who loses credulity when he warns a loved one ahead of the general public, or an official kidnapped by people desperate to obtain doses of a new vaccine.

It darts from subplot to subplot, and only the uniform excellence of the cast keeps us attached to these stories. (I counted eight Oscar nominees or winners.) Soderbergh, who also did the fine cinematography, hired stars who inspire sympathy: Matt Damon, Laurence Fishburne, Kate Winslet. Though their characters remain mere sketches, our long-standing affection for these actors keeps us interested in the people they play. (The exception is Jude Law, who often plays unsympathetic guys. Sure enough, he turns up as a shady blogger who manipulates the crisis to make himself rich.)

What the movie does best is give us a shorthand view of the arc of a disease, from detection to mass infection to national panic, while doctors search for a cure. That picture is not a reassuring one.

Scientists and public officials all attack the problem diligently and courageously. (This is like an anti-conspiracy movie, where the heroes all work for the government or a big nongovernment organization.) Winston-Salem native Jennifer Ehle stands out as a tireless doctor who commits a selfless act most of us wouldn't dare to do; Elliott Gould plays a veteran, renegade researcher who manages to grow the virus in a lab, where it can be studied.

Meanwhile, ordinary folks loot stores, kill neighbors, knock kids out of the way to get food or medicine and do the stupidest things possible. (Really, with a worldwide epidemic raging, who would still shake hands with strangers? And why does nobody cover a mouth while coughing ferociously?) We learn that adultery contributed to this disaster: A wife who's between planes in Chicago sleeps with an old boyfriend and unknowingly gets the deadly ball rolling in America's third-largest city.

Burns and Soderbergh reserve their worst scorn for the Internet. Credulous dopes hearken to Law's sleazy blogger, who claims to get up to 12 million unique hits a day. He recommends Forsythia, an untested homeopathic remedy, on his site. When he says it cured him of the infection he actually never had, his stock in the company that makes it shoots upward. (This also lets the filmmakers indict inside traders.) Law's character seems to make sense at times, as many online scumbags do; he digs up genuine statistics for his own purposes, the way the Devil is said to quote scripture.

The movie isn't a howdunit: We don't need to know who infected the first sufferer before she became a plague-carrier to the world. In fact, the story begins with a title card reading "Day 2."

But at the end, as the words "Day 1" appear onscreen, we finally see the random and seemingly innocuous events that will lead months later to the deaths of millions. That's when the horror fully hits us: "Contagion" declares that such a catastrophe is inevitable in our ever-more-connected world.