A new center that is the first in the nation intended to study the spread of deadly diseases from animals to humans will be dedicated Saturday at Washington State University. The facility is a centerpiece of WSU’s expansion into a new field of research by creating the School of Global Animal Health. “Somewhere between 60 and 75 percent of the diseases that infect humans over time have their origin in animals,” said Guy Palmer, a professor of pathology and infectious diseases at the university’s College of Veterinary Medicine. “You want to control the disease before it comes into humans.”