Hundreds of West Africans could be carrying the deadly Ebola virus and not know it, potentially infecting hundreds more, as cash-strapped governments and overwhelmed aid agencies struggle to contain the virus's spread

At least 1,500 people have not yet been traced who are known to have come into contact with others confirmed or suspected to be infected with the hemorrhagic fever, Medecins Sans Frontieres said. Many more could be moving freely in the three countries battling the virus, Guinea, Liberia and Sierra Leone, but fear of the illness and mistrust of Western medicine means that they refuse to come forward to speak to doctors. The current outbreak is the worst ever. So far 467 people have died and health staff have identified at least 292 other suspected or confirmed cases. Ebola is transmitted by coming into contact with bodily fluids of an infected person. It has no cure and as many as 90% of its victims die, often from uncontrollable internal and external bleeding. The outbreak was now out of control in the three affected countries and could quickly spread across West Africa, according to MSF, which is leading efforts to deal with cases.