Viruses are invisible and respect no boundaries.
He heads the Division of Virology and the Viral-Immunobiology Laboratory at The Scripps Research Institute. Viruses have been around since antiquity, killing millions and shifting the world's balances of power, Oldstone said. Yellow fever, for one, spurred the African slave trade, shut down the national government and made it easier for the United States to expand west. Reviewing the effects of smallpox over five centuries, Oldstone said the deadly, disfiguring virus helped the Spanish conquer Mexico and Peru in the 16th centuries. Smallpox, along with measles, decimated the Aztecs even though the Indians greatly outnumbered the Spanish.