We know there are certain ...

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.
 Nathan Wolfe

Quotes from the same author

Don't assume that what we currently think is out there is the full story. Go after the dark matter, in whatever field you choose to explore.
 Nathan Wolfe
About 20 percent of the genetic information in your nose doesn't match anything that we've ever seen before.
 Nathan Wolfe