ESPN Outdoors (Internet / TV) 02/21/06 Humans risk being overrun by diseases from the animal world, according to researchers who have documented 38 illnesses that have made that jump over the past 25 years. That's not good news for the spread of bird flu, which experts fear could mutate and be transmitted easily among people. Bird flu has killed at least 91 people — most of them in Asia — since 2003, according to the World Health Organization. It appears to kill about half the people it infects. However, should it mutate so it can pass from human to human, it likely will grow far less deadly, said Dr. Stanley Lemon, of the University of Texas Medical Branch at Galveston. "It is very unlikely that it would maintain that kind of case mortality rate if it made the jump," Lemon said. (This Associated Press article continues to appear throughout the United States and abroad on TV and in Print.)