The Bill and Melinda Gates foundation is leading a group of donors that has pledged a combined $635 million to renew the international campaign to eradicate polio, following an increase in polio cases that spread to seven other countries. The Gates foundation has pledged $255 million, the Rotary Foundation has promised its members will raise $100 million and the German and U.K. governments have together pledged $280 million, according to a Wall Street Journal report. Report