We humans are in many ways a species of Gullivers, bound and occupied by an army of the very small organisms that really rule this planet. The world is a fully globalized marketplace for the very small.
National borders can constrain trade in goods and currency, but they are useless against disease.
Pathogens move freely and widely, carried by travelers, humans and others, as well as by the wind. We must realize that we cannot block diseases by closing borders, by signing or banning trade agreements, by national policies or by local practice. We must fashion a global response to a global problem. Antiglobalism must give way to a planetary perspective on public health. In many ways, we have brought these problems on ourselves.