Polio has been gone from the U.S. since 1979. But for several other countries, it's an ongoing threat.
That's not to say there hasn't been tremendous progress. Since the introduction of a vaccine in 1988, reported cases have decreased by more than 99 percent - from an estimated 350,000 to just 223 in 2012.
And now, India is approaching three years without a single case of polio. According to BBC, the World Health Organization is expected to formally declare India "polio-free" next month.
In anticipation of this milestone, the Gates Foundation shared a GIF that recaps all the recent progress. Three countries are still in a chronic fight against the disease: Nigeria, Pakistan, and Afghanistan.
Top image: A Pakistani child receiving a polio vaccine in Islamabad, Pakistan last November. (Muhammed Muheisen/AP)