Late last night, I posted a thread on this under the generalized cruise questions board. This is nothing to be sneezed at, no pun intended. It is a never before seen amalgamation of 2 swine, one avian, and one human strain. It is htiing the robust -- 20 to 40 the hardest. All deaths in Mexico City were between 27-37. It looks like cytokine storm, an overreactive immune system reaction causing the deaths, which is believed to be what happened in the 1918 flu pandemic which took those in mid range, unlike the seasonal flu which takes those very young, and old, generally.
I would think that excursions to Mexico would be closed down shortly -- it's about stopping a pandemic. A first step, as another reported, is being taken by the government saying no unnecessary travel, there. With Asian countries checking anyone who has been to Mexico, you can bet the same will be done with people coming off ships who have been near the affected area, and the Yucatan is one such area, as the NY and New Zealand cases came from CanCun.