The Bill & Melinda Gates Foundation announced $1.2 billion on Sunday for efforts to eradicate polio worldwide. Polio was paralyzing tens of thousands of children a year in dozens of countries around the world just a few decades ago, but the virus is now only endemic in Pakistan and Afghanistan. Part of the success in eradicating the virus is due to the nearly $5 billion that the Gates Foundation has contributed to the Global Polio Eradication Initiative. This 1964 microscope image made available by the U.S. Centers for Disease Control and Prevention shows damage from the polio virus to human spinal cord tissue. (Dr.