Scientists at the Center for Infection and Immunity (CII) at Columbia University Mailman School of Public Health estimate that there is a minimum of 320,000 viruses in mammals awaiting discovery. Collecting evidence of these viruses, or even a majority of them, could provide information critical to early detection and mitigation of disease outbreaks in humans. This undertaking would cost approximately $6.3 billion, or $1.4 billion if limited to 85 percent of total viral diversity – a fraction of the economic impact of a major pandemic like SARS. Close to 70 percent of emerging viral diseases such as HIV/AIDS, West Nile, Ebola, SARS, and influenza, are zoonoses – infections of animals that cross into humans. Yet until now, there has been no good estimate of the actual number of viruses that exist in any wildlife species.