A key moment in the battle against the world's deadliest outbreak of Ebola will be reached on Tuesday when Guinea, the first of three west African states struck by the epidemic, is set to be declared free of the disease.

One of the poorest nations in the world, Guinea leapt to global prominence after becoming the host country for "patient zero" - an infant, Emile Ouamouno, who on December 2013 became the outbreak's first victim.

The fever spread stealthily and terrifyingly, striking two neighboring countries, Sierra Leone and Liberia, with sporadic cases also in Mali, Nigeria and Senegal.