We had an East Indian grocery here in the states a few years ago. I noticed that the customers were not prone to getting ill with common infectious diseases, although sinus problems were common, and the older ones tended to have heart conditions.
If you listen to some of the stories from people who have grown up in a third-world country it is not difficult to believe they have developed immunity to a broad spectrum of communicable disease (they certainly get sick when home). If you couple that with the (tentative) finding that they have or don't have (I can't remember which) a gene that diminishes the hyper-autoimmune response seen in SARS, maybe they do have something going for them.
I wonder if the ship had, say 24 Norwegians, how many would be sick?
Sorry, I meant to ping these people on my last post about the hypothesized Indian immunity...