Imposing quarantines over areas affected by some sort of plague is nothing new; doing so for other reasons isn't new either.
Mexico has been the unfortunate country in this case, where swine flu or influenza has taken the highest toll of human lives and at the moment of this writing, a number of countries have already announced that they will prohibit or limit travel to and from that North American country for a while despite the arguments and advice of the World Health Organisation (WHO) that explicitly recommends not to do that. The Mexican government, in turn, has accused some of those countries of discrimination, and this is something that deserves some analysis.
The first thing that we have to understand is that there is a lot of fear among people; this translates into political fear and that is why leaders take such measures: Aside from true sanitary concerns, they don't want to become political victims of this situation.
But can the disease be stopped by disallowing travel? Simply stated, no. Just consider this: You cannot stop the world, no government will do that, and even harassing people at airports will not stop the problem. There are ships at sea, there are trekkers in the mountains, armies, animals, winds, food, and even smugglers that simply cannot be stopped. If it takes one person to bring an infection such as this across the border of any country, then it becomes obvious that since no government can stop and control everyone and everybody, the answer results obvious.
It is nice and useful to review history when something like this happens because pandemics are nothing new, and past experiences could teach us a lot, if not about medical technology, at least about sociology and the way in which people behave under such circumstances. And so, we can go back to the mother of all plagues, which was the Black death of the fourteenth century, that we often portray as an example both because those events are well documented and for the magnitude that it had: It was a true end of days, since almost half the human population of the world perished.
Back then, controls and quarantines were impose even by the use of lethal force; just in Europe, what began in some ports in southern Italy ended up corroding the whole continent. This means that no control or quarantine worked, whatsoever. Then, people found also a scapegoat: The Jews, and so, pious believers of other religions began exterminating Jews because they thought that somehow they were behind the thing, conspiring to kill all God loving people in the planet, as usual, right?
Well, those pious and faithful folks seemed not to realise that Jews were dying at the same rate than Christians and Muslims due to the plague, or it didn't matter a tall.
So, the assumption that quarantines and controls that are now specifically targeting Mexicans and people coming out of Mexico is not only baseless by being limited as such in its scope, but probably also demonstrates that the government of Mexico is right and there is indeed some sort of discrimination, and it only takes a thought to find that out positively: The United States has even more inhabitants than Mexico and the number of cases of this infection is already in the hundreds, so whether it is four hundred in Mexico or two in the USA, it matters little except for one thing: Those stats indicate that the virus has already established itself very comfortably in both nations, so, if the controls imposed on people coming from Mexico were really sensible, they should be also performed on everyone coming out of the United States of America.
This chain of reasoning doesn't not imply that the virus should be left at large to continue its rampage unabated, but the people as well as their leaders should remain able to discern between what is sensible and what is agreed only because of fear and the lobby of isolationist, segregationist or racist groups that are simply trying to gain something from this tragedy.