The man who reinvented computers and made PCs a household item in most wealthy nations, Microsoft tycoon turned philanthropist Bill Gates, is now focusing his attention on recasting the WC.

The Bill and Melinda Gates Foundation is pledging millions of dollars in grants to reinvent the toilet, its director of water, sanitation and hygiene programs, Frank Rijsberman, told AFP, calling it a "huge issue for Africa."

The aim is to boost health in developing countries by giving the 2.6 billion people who don't have access to a WC a hygienic, safe place to go to the toilet.

Speaking by phone from a pan-African conference on sanitation that opened in the Rwandan capital Kigali Tuesday, Rijsberman said only a fraction of Africans, even in large cities, are "connected to sewers with a flush toilet."

"In cities, people use 'flying toilets,'" he explained.

"They go on a plastic bag and then throw it in the street, which is not only gross but kids walk around and play, and come into contact with the poop and can develop chronic diarrhea, which kills more children under the age of five than HIV/AIDS and malaria."

Rijsberman mentioned Haiti, where by the end of last month 5,500 people had died from a cholera epidemic he said was caused by "improperly disposed-of waste" from a UN peacekeepers' base.

Giving people in Africa and other parts of the developing world access to toilets could slash the death rate from diarrheal disease by around 40 percent, he said.

But the Gates Foundation not only wants to improve access to toilets, it also wants to get away from the flush WC that is ubiquitous in the West but isn't a viable solution for poor countries.

"We need to reinvent the toilet. We need to come up with new technology that doesn't put waste into drinking water, doesn't flush it down a very expensive pipe to a waste water treatment plant where we spend lots of money to remove the poop," Rijsberman said.

To spur the reinvention of the WC, the Gates Foundation used the AfricaSan conference in Kigali to announce $42 million in grants to spur innovations in the capture and storage of waste, and to develop ways to process what Rijsberman calls "poop" into reusable energy and fertilizer.

Among the ideas being worked on are a waterless toilet, and a system that would microwave fecal matter and turn it into fuel.

The foundation says the reinvented toilet must be affordable, costing no more than five US cents a day per person. It also has to be easy to install, use and maintain.

"We have to learn to not think of poop as a nuisance and waste but as a resource that could be recycled at a cost of a few cents a day," Rijsberman said, citing the example of Indian villagers who dry cowpats to use as fuel.

The foundation has teamed up with global partners including the US Agency for International Development (USAID) to develop new tools and technologies to improve sanitation and make toilets accessible to the world's poor.

Rijsberman was hopeful that investments in sanitation innovation would produce several new-breed toilet prototypes within a year, with reinvented toilets hitting markets in the developing world in around three years.