Bill Gates has vowed to help end the scourge of polio in Nigeria. The latter is Africa's most populous nation and is still blighted by the debilitating disease.
"This is my fourth visit to Nigeria and every year I come I see us get closer to our goal of polio eradication," Gates said at a stakeholders' forum on the issue.
Africa's richest man, Aliko Dangote, attended the forum, as did President Goodluck Jonathan and other dignatories and religious leaders including the supreme head of Muslims in Nigeria, the Sultan of Sokoto, Sa'Ad Abubakar.
Gates, wearing a traditional Nigerian flowing gown (boubou), said some parts of the country were slowing the overall progress made because they had failed to run campaigns and do follow-up work.
He urged a presidential task force working on polio eradication "to track these gaps", urging greater interaction between campaigners.
Jonathan applauded the Microsoft founder "for his commitment to help Africa solve its health problems".
"There is no reason we should not eradicate polio by 2014. Let me assure you that the federal government is totally committed to eradicating polio," Jonathan said.
Health Minister Onyebuchi Chukwu said Nigeria had reduced by 50 percent the "Type A" polio virus, though 51 cases had recently been reported.
Jonathan announced the conferment of one of the nation's most prestigious honours, the Commander of the Federal Republic, on Gates in appreciation of his contribution to wiping out the disease.
Speaking earlier at a meeting with leaders of the Nigerian parliament, Gates said the goal to eradicate polio in the country was possible.
"The goal of saving lives is a very realistic goal. Through these efforts I do think that children who do survive will be far healthier and able to take advantage of their education and contribute to the success of Nigeria."
Polio is caused by a highly infectious virus that invades the nervous system through the mouth and can cause irreversible paralysis within a matter of hours.
Among those paralysed, between five and 10 percent die when their breathing muscles fail to work. Children under the age of five are those most at risk.
Infection typically occurs through water that carries the virus.
There is no cure for the disease, but there are highly effective vaccines to prevent it.
In 1988, polio was endemic in 125 countries, but by 2012, this was reduced to three countries -- Afghanistan, Nigeria and Pakistan -- where health systems are poor and vaccination campaigns have been disrupted by Islamists.
Nigeria has since 2009 been battling an Islamist insurgency in northeastern Nigeria which has claimed thousands of lives.