First, the food buffet was shut down as gloved staff scurried about wiping every surface in sight. Then the ocean liner's gym, bar, casino and boutiques were closed, with passengers urged to keep to themselves. Finally, they were confined to their staterooms.

Once the captain announced their vessel may be tainted with coronavirus, Grand Princess cruise ship guests like Kathleen Reid were left with little to do but contemplate the prospect of extended isolation at sea, or worse.

"My first reaction was, 'Oh, crap. We're going to be quarantined, and maybe get sick,'" Reid, 67, a retiree from Granbury, Texas said. "We don't know what's happening, so we're just kind of in limbo, waiting."