LAURIE GARRETT: In 1918, my now quite elderly uncle was a young boy, and the flu came through. And his family insisted that he could not go outside for any reason until the whole epidemic was over. He spent his afternoons looking out the window and counting the hearses going up and down the neighborhood and trying to guess which of his schoolmates had died and keeping a little scorecard.
BRIAN ROSS: That was before the international air travel routes of today with non-stop flights from flu ground zero to the United States.
BILL KARESH: So it's going to come out of Bangkok or Hanoi or Hong Kong or Shanghai, get into Japan. It'll get to New York. It'll get to San Francisco. It'll get to Vancouver. It'll get to Paris and London, all within a matter of the first week.
LAURIE GARRETT: It's on people's hands. You shake hands. You touch a doorknob that somebody recently touched.
BRIAN ROSS: And that's how this particular strain, never seen before, could spread?
LAURIE GARRETT: Absolutely. There's no reason to believe that if H5N1 manages to make that crucial punch through genetically, it won't spread like every other flu.
BRIAN ROSS: And once it hits a city like New York ...
DR. IRWIN REDLENER: It's extremely possible we'd have to quarantine hospitals, we'd have to quarantine sections of the city.
BRIAN ROSS: Dr. Redlener has been working with New York City officials to get ready for the deadly epidemic.
DR. IRWIN REDLENER: The city would look like a science fiction movie. This would look like an armed camp, basically.
BRIAN ROSS: You would ring a neighborhood in New York City with armed officers to keep people from leaving or going in?
DR. IRWIN REDLENER: Yes.
BRIAN ROSS: Actually shut down parts of New York City?
DR. IRWIN REDLENER: We might have to do that, correct.
LAURIE GARRETT: I could imagine that you would look at Grand Central Station and not see much of anybody wandering around at all. People would be afraid to take the subways because who wants to be in an enclosed airspace with a whole lot of other strangers never knowing which ones are carrying flu?
DR. IRWIN REDLENER: We might be seeing 200 to 350 people every single day dying from the flu in New York City.
BRIAN ROSS: Every single day?
DR. IRWIN REDLENER: Every single day. And a quarter to a third of those might be children.
BRIAN ROSS: And for hospitals, there would be scenes like the ones this month in Houston and New Orleans. Except the cots would be full of dying people.
LAURIE GARRETT: There wouldn't be equipment and personnel to staff them adequately that you could really call them a hospital. You might more or less call them warehouses for the ailing.
BRIAN ROSS: And as happened in New Orleans, there would be no place for the dead.
MICHAEL OSTERHOLM: If you look at the expected number of deaths that could occur in cities across the United States, we are wholly unprepared to process those bodies in a dignified and respectful way. We will run out of caskets literally within days.
BRIAN ROSS: University of Minnesota Professor Michael Osterholm is the director of the Center for Infectious Disease Research.
MICHAEL OSTERHOLM: That's the kind of realities that we have to start planning for now that unfortunately in most communities in this country we just haven't even begun to think about.