American passengers from the hantavirus-stricken cruise ship are now back on U.S. soil. Tonight, at least one patient remains in a biocontainment unit after testing positive, while another is undergoing evaluation. Now, new questions are emerging: How long could their quarantine last? We’re taking a closer look at the massive operation that transported patients to Nebraska, as well as the two additional passengers flown to Atlanta for monitoring. And as other countries move to mandate quarantines, growing questions remain over whether the United States should follow suit. For more context and news coverage of the most important stories of our day, click here: nbcnews.com » Subscribe to NBC News: nbcnews.to/SubscribeToNBC » Subscribe to Here's the Scoop podcast: nbcnews.com/heres-the-scoop-daily-podcast Every day, NBC News helps people understand what’s happening and why it matters — through fact-based reporting, meaningful conversations, and powerful s...