The last push to eradicate polio from the face of the earth received a vital boost yesterday with a $200m (£96.5m) cash injection from Rotary International and the Bill and Melinda Gates Foundation.

The donation was last night celebrated by Rotarians throughout Scotland, who have raised £2m to wipe out the disease which paralyses and kills children.

The announcement came at a time when some worried that the campaign to vanquish the virus would fail in its final stages.

Although efforts to beat polio have slashed the number of cases by 99%, the virus persists, mainly in Nigeria, India, Afghanistan and Pakistan.

To make the final push, Rotary International will receive a $100m (£48.2m) grant from the Gates Foundation. In response, the worldwide organisation of business leaders pledged that it would match that $100m over a three-year period.

An initial $100m will be spent to boost mass immunisation campaigns in the polio-affected countries, carried out by the Global Polio Eradication Initiative (GPEI), a partnership spearheaded by the World Health Organisation (WHO), Rotary International and Unicef.

However, the $200m, while welcome, still falls short of the total required to eradicate polio, which will ultimately cost another US$1bn (£483m) according to Dr David Heymann, WHO's top polio official.

The eradication of the disease has been Rotary's top priority since 1985. Since then, rotarians worldwide have contributed $633m (£305m) to the eradication effort.

Drew Hughes, district governor for Rotary International in the west of Scotland, said: "When Rotary first decided to take on polio, back in the 1970s, I thought - we've got no chance'.

"At that time, around 350,000 people in 20 countries were either dying of or suffering from polio. Today, the sufferers number less than 2000.

"That difference is thanks in a large part to the efforts of Rotarians in Scotland. Members in my own District 1230, which stretches from Stranraer to Fort William, have raised around £500,000."

The money was donated to the Global Polio Eradication Initiative, involving more than 200 countries, which has cut the number of polio cases from 350,000 in 1988 to 1997 cases in 2006.

But geographic isolation, armed conflict and cultural barriers have kept them from reaching people in the four countries where the disease remains endemic.

Mr Hughes said: "One of our global campaign's most impressive achievements is that Rotary International is succeeding in getting into conflict zones and highly dangerous areas to immunise children.

"We are trying to persuade the Mullahs that we are not poisoning their children and we seem to be succeeding.

"Even the Taliban have started allowing Rotary into areas they control. That is the standing which Rotary International now has."

Bill Gates, co-chair of the Bill & Melinda Gates Foundation, said: "The extraordinary dedication of Rotary members has played a critical role in bringing polio to the brink of eradication. Eradicating polio will be one of the most significant public health accomplishments in history, and we are committed to helping reach that goal."

Dr Robert Scott, who leads Rotary's polio eradication effort and chairs the Rotary Foundation, said: "Rotary members worldwide have worked very hard over the years to reach this point, and it is rewarding to see our approach validated in such a significant way by the Bill & Melinda Gates Foundation.

"We hope that this shared commitment of Rotary and the Gates Foundation will challenge other donors - including foundations, governments and non-governmental organisations - to step up and make sure we have the resources needed to rid the world of polio once and for all."

In October, WHO said there has been significant progress in India and Nigeria, which together account for most of the world's 735 reported polio cases so far in 2007. This compares to 1686 reported cases at the same time last year.

Officials from the World Health Organisation say that yesterday's donation will help to finish the virus off, once and for all.

"This investment is precisely the catalyst we need as we intensify the push to finish polio," said Margaret Chan, director-general of the World Health Organisation.

"We have the technical tools to do it, and we can achieve a polio-free world if the rest of our financial partners step up to meet the challenge."

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