UC Davis will bring on emerging-disease authority Stephen S. Morse of Columbia University Mailman School of Public Health as director of PREDICT. Morse said that, historically, pandemics -- epidemics that spread around the world -- occurred perhaps every 30 to 40 years. "But in our modern world, the chances of novel diseases or even a new pandemic emerging are higher than ever, because of how we live and the extent to which we travel, Morse said. "Our human settlements and roadways push deeper into forests and wild areas where we now raise livestock and poultry; and we transport ourselves, our animals and our food farther and faster around the globe."

Those conditions enable the spread of microbes, especially viruses and bacteria, from animals to humans. Among the 1,461 pathogens recognized to cause diseases in humans, at least 60 percent are of animal origin.

Notable outbreaks of these animal-to-human diseases, or zoonoses (pronounced ZO-oh-NO-sees), include:

The 1918 influenza pandemic, which was probably caused by a virus that jumped from birds, killed over 50 million people globally;

The human immunodeficiency virus (HIV), which moved from chimpanzees to people, now infects more than 33 million individuals;

Severe acute respiratory syndrome (SARS), which emerged in 2003 from southern China "wet markets" where wild animals are sold for food; and

The recent outbreaks of avian influenza H5N1, or "bird flu."

In a global pandemic today, a quarter of the world's population could be infected and between 51 million and 81 million people could die, with the toll in the United States exceeding 400,000 deaths. World economic losses are estimated to exceed $4 trillion.

Source: University of California - Davis