A new report on global giving shows there has been a big shift in recent years in who is giving and receiving international aid. The U.S. remains the largest donor, giving out more than $30 billion each year. But now large sums of money are coming from private foundations and corporations and even countries who only a few years ago were recipients themselves.

The World Health Organization released a six-year plan to wipe out the remaining pockets of polio and ensure the virus doesn't come back. With fewer than 20 polio cases so far this year, the world is closer than ever before to eradicating polio.

Northern Nigeria is the only region in the world where the number of polio cases is on the rise. International groups have poured money and volunteers into the area to combat the disease. But vaccinators face daunting challenges 鈥� from security threats like terrorist bombings to a lack of basic resources like electricity.

Polio is deadly, but so is what's required to stamp it out once and for all in Pakistan: facing down Islamist extremists. The virus thrives in Pakistan's lawless 鈥� and largely inaccessible 鈥� tribal regions. To stop polio's spread, health workers must be courageous, clever and relentless.