Karl M. Johnson, the virologist who has identified more new killers than any other living scientist, concurs. They can go in and chop and cleave and do this or that to the viral genome, and soon you'll know why this hantavirus strain attacks the pulmonary system and why that one attacks the kidney or the heart. A genome here, a genome there and ordinary human contact can do the rest. D.C. There, in these places so beloved by romantic environmentalists, lie seething cauldrons of diverse species, each with its own army of parasites, each one of which must be eyeing the growing mountain of succulent human flesh. The bug that can sink its teeth into that flesh wins the jackpot.
Nature is more treacherous than most environmentalists understand.
Even as we deify her, she is looking for ways to undo us. It's as simple as that. Early settlers cut down the trees for farmland, shot the deer for venison and scared away the field mice, together with the pinhead-size ticks that feed on them and us. They thus deprived Borrelia burdtdorferi, the Lyme bacterium, of the links in its life cycle. Ignore it or treat it too late, and you will suffer from chronic debilitation.