We may have charted all the continents on the planet, and we may have discovered all the mammals, but that doesn't mean that there's nothing left to explore on Earth.
Because pandemics almost always begin with the transmission of an animal microbe to a human, it's work that takes me all around the globe - from rain forest hunting camps of central Africa to wild animal markets of east Asia.
The reality is: By the time swine flu got on the radar screen of global public health, it had already spread. It was already in the States, it was in Mexico, it was in New Zealand. By the time it reaches that point, you've lost the ability to contain it.
Pandemics do not occur randomly. From malaria and influenza to AIDS and SARS, the lethal microbes have come, in the first instance, from animals, especially wild animals. And we increasingly know which parts of the world pose the greatest risk for future incursions.
When there is an influenza threat, drop everything and focus on risks from influenza pandemics. When SARS spreads, focus on unknown respiratory diseases. This approach helps to quell public concern, but it's a hugely inefficient way to deal with future risks.
We know there are certain types of viruses that are nasty - influenza, for instance, is an area that is not a blindside. But a lot of viruses have come out of nowhere, like H.I.V., or to a certain extent SARS. Because we know we have the potential to be blindsided, we really have to investigate the unknowns.
