Polio is in its final days.
The disease that once paralyzed hundreds of thousands of kids a year around the globe is now down to just a few dozen cases this year. "We are aiming to halt all transmission of wild polio virus next year," says Peter Crowley, the head of UNICEF's global efforts against polio.
If polio is stopped, it will be only the second human disease to be eliminated. Smallpox was the first — the last case was in 1977.
There's reason to be optimistic that this gigantic feat of public health is within humanity's grasp. The World Health Organization says polio transmission has stopped for the first time ever in Africa. Last month, Africa's last bastion of polio — Nigeria — celebrated going an entire year without recording any new cases.
The red dots on the map below show how cases continued to pop up over a wide belt in the middle of the continent from 2010 until 2014.
"This is a really major step forward in the effort to eradicate polio from the world," says Kate O'Brien, a professor at the Bloomberg School of Public Health at Johns Hopkins. O'Brien also works with the World Health Organization as an adviser on global immunization policy. She calls ending polio in Nigeria "absolutely massive" in the overall eradication effort.
With Nigeria off the list of countries where the virus is self-sustaining, there are now just two nations in the world where transmission has never been fully stopped: Afghanistan and Pakistan. Of the 51 cases of wild polio detected globally so far this year, all of them have been in those two countries. (Note: The world map at the top of this post also includes cases of vaccine-derived polio, which are easier to control.)
The problem is that until polio is actually stopped in Afghanistan and Pakistan, the multibillion-dollar global effort against the virus is going to have to continue everywhere.
"This is a virus that is fighting for its life," O'Brien says. "It is going to find people and places that are not vaccinated. It's going to find a way to move and it's going to find those places that are vulnerable." Kids will continue to be vaccinated everywhere around the world for at least three years after the last case to make sure that the virus doesn't stage a comeback.
Public health officials have been declaring that polio is on the verge of being wiped out ever since Jonas Salk and Albert Sabin came up with vaccines against it in the 1950s. At that point the world was tallying hundreds of thousands of cases each year. Now, it's just a few dozen cases globally, and polio's demise does appear closer than ever. The disease that in its heyday affected Franklin Roosevelt, Olympian Wilma Rudolph and actors Mia Farrow and Donald Sutherland will be relegated to the history books.