On Wednesday, tycoon Bill Gates announced that his foundation, along with the charity group Rotary International and the British and German governments, would be donating more than $630 million to the attempt to eradicate polio.

The measure comes after the disease has spread to seven countries that had been polio-free.

Nevertheless, even with this amount of money, the campaign to fight polio is still $340 million short so as to get through 2010, while the World Health Organization (WHO) has estimated that another $2 billion would be necessary until 2013, when hope is that the disease would have been eradicated.

Bill Gates, the co-chair of the Bill & Melinda Gates Foundation, which donated $255 million, stated that he was optimistic about the outcome of the attempt to wipe out polio.

Polio, which mostly affects children under 5, is a water-borne disease that can cause paralysis and sometimes even lead to death.

Since the World Health Organization and its partners launched the campaign aimed at eradicating polio back in 1988, the disease has dropped by more than 99 percent, still the number of cases, which amounts to 2,000 on an annual basis, has not decreased in eight years.

In addition, the original initiative was to get rid of polio in 2000, which was afterwards extended to 2005, while now, even though no official deadline has been set, Dr. Bruce Aylward, WHO's director of polio eradication, said that many countries hoped it to be 2013.

Polio is still affecting people in countries such as Afghanistan, India, Nigeria and Pakistan.