The Bill and Melinda Gates Foundation is to spend US$437 million funding 43 research projects that aim to overcome 'grand challenges' to tackling diseases such as tuberculosis and malaria in the developing world.

The foundation's Grand Challenges in Global Health initiative announced the plans yesterday (27 June).

The 14 challenges were identified in 2003 from more than 1,000 suggestions made by scientists worldwide (see Researchers asked for 'top medical roadblocks').

The challenges include making staple crops more nutritious to combat malnutrition, and developing vaccines that need no refrigeration and so can be transported in regions without electricity.

Genetically engineering mosquitoes in areas where dengue fever is rife so that they die before they can pass on the virus, and creating handheld kits for rapidly diagnosing diseases, are also on the list.

Among the researchers whose projects have been selected for funding is Paul Yager at the University of Washington, United States, who with colleagues is developing a hand-held device that would allow health workers in remote areas to analyse a blood sample and diagnose a range of diseases in just ten minutes.

Several researchers in the United States will use the funds to develop needle-free vaccines to ensure that more children in poor countries are immunised against common diseases.

James Baker and colleagues at the University of Michigan, for instance, are developing a method of making 'nose drop' vaccines, and scientists at the US company Aktiv-Dry are working on a measles vaccine that can be inhaled as a powder.

Despite millions being invested each year in global health, only a small percentage is spent on health problems affecting the developing world, where 90 per cent of the global population lives.

The Bill and Melinda Gates Foundation launched the multimillion-dollar Grand Challenges initiative in 2003 to redress this balance.

"It's shocking how little research is directed toward the diseases of the world's poorest countries," says Bill Gates.

"By harnessing the world's capacity for scientific innovation, I believe we can transform health in the developing world and save millions of lives."

In its call for research proposals, the initiative placed a strong emphasis on practicality. The results of the projects — whether vaccines, crops or medical procedures — must be usable in developing countries, says Richard Klausner, a member of the Grand Challenges scientific board.

"Scientific advances are of little value unless they are accessible to the people who need them," he said.