In the race for the world's top health post—director general of the World Health Organization—the two front runners are from Africa and Mexico.

WHO unveiled a list of nine candidates, seven of them from developing countries, for the role of director general of the United Nations agency from July next year, when the present incumbent, Gro Harlem Brundtland, retires.

Insiders say it is unlikely that the present director general, a former prime minister of Norway, will be succeeded by another candidate from the developed world.

That would effectively rule out the Belgian epidemiologist and microbiologist Peter Piot, who heads UNAIDS (the joint UN programme on HIV and AIDS). Piot, 53, originally made his name as one of the doctors who helped isolate …