UN Secretary-General Ban Ki-moon immunizes a boy against polio during Angola’s first polio eradication campaign of the year. UN Photo/Quintiliano dos Santos

Wild viruses and wildfires have two things in common. If neglected, they can spread out of control. If handled properly, they can be stamped out for good. Today, the flame of polio is near extinction — but sparks in three countries threaten to ignite a global blaze. Now is the moment to act.

During the next two weeks, on two continents, two events offer the chance for a breakthrough. First, the leaders of the world’s largest economies, the G8, congregate at the U.S.presidential retreat at Camp David in rural Maryland. A week later, the world’s ministers of health convene in Geneva. Together, they can push to deliver on an epic promise: to liberate humankind from one of the world’s most deadly and debilitating diseases.

Polio today survives in only three countries: Afghanistan, Nigeria and Pakistan. That’s the good news. The bad: we are in danger of falling victim to our own success.

Here’s why: the world is now populated by a generation which has either never been exposed to polio or has been inadequately vaccinated. When the virus strikes under those conditions, the impact can be devastating. We saw that in the Republic of the Congo in 2010 and elsewhere in Africa when an outbreak killed half of all who were infected. A prompt emergency response by the international community halted that budding epidemic. But the incident gives an idea of the potential consequences of failing to eradicate polio while we have the chance. This year fewer than 100 people were left paralyzed by this easily preventable disease, almost all in the three countries I have mentioned. Left unchecked, however, UN epidemiologists warn that a renewed outbreak could cripple as many as one million people within the decade, many of them children — the most vulnerable of the vulnerable.

This threat keeps me up at night because I know how easy it is to address. My wife and I have personally immunized toddlers in Asia and Africa, joining tens of millions of government workers, Rotarians, volunteers, political and religious leaders (not to mention parents) who have worked for decades to ensure that every child is protected. Most recently, we visited India, which just two years ago was home to half of all the world’s children with polio. Now, thanks to a concerted drive, we were able to celebrate India’s first polio-free year in history.

The United Nations, with its partner Rotary International, is driving the global campaign. Our agencies are working hard to reach all children, including those in refugee camps or swept up by natural disasters and hunger emergencies.

The Global Polio Eradication Initiative has only half of the $2 billion it needs to procure vaccines and deploy staff to the last bastions of the disease. Now is the critical moment. If we can cover a relatively modest $1 billion shortfall — we can save the world an estimated $40-50 billion in the cost of treatment by 2035, not to mention many lives and many young futures.

When the world’s health ministers gather in Geneva later this month, they will declare a global public health emergency and call on the world to response to the threat of a resurgent polio. As the G8 leaders meet at Camp David, they should be aware of what is coming — and recognize this great opportunity to act in the name of the world’s people.

Those meetings will soon be followed by others: the annual gathering of the G20 in Mexico, the Rio+20 conference in Brazil and the European Union summit in Belgium. I hope polio will be on the agenda. I appeal to all leaders, everywhere, to act now to protect future generations. By funding the Global Polio Emergency Action Plan for the next two years, we can make the threat of polio a distant and fading memory.

Learn more about Rotary’s efforts to eradicate polio