Health officials now believe that it is here that the fight will be won or lost.
Already there are thought to be 20,000 victims and there is a real danger that the figure will increase unless stricter steps are taken to prevent contacts among the populations of all three countries.
On Friday, at a regional summit in the Guinean capital of Conakry, Aboubacar Sidiki Diakité, head of Guinea's ebola task force, said: "Currently, some measures taken by our neighbours could make the fight against ebola even harder. When children are not supervised, they can go anywhere and make the problem worse. It is part of what we will be talking about."
Part of the problem has been the free movement of people throughout West Africa and the porous national borders. One casualty has been the African Union military mission in Somalia, where a planned rotation of the Sierra Leonean infantry battalion has been postponed in an attempt to prevent the virus crossing into the country.
Dealing with the military has been comparatively easy, as has been the closing of official frontier and customs posts. It is in country areas with unrestricted borders that the real problem lies. Doctors such as Bart Janssens, director of operations at the charity Médecins Sans Frontières, has warned that governments and global bodies have no "overarching view" of how to tackle the current crisis.
He said: "This epidemic is unprecedented, absolutely out of control and the situation can only get worse, because it is still spreading … If the situation does not improve fairly quickly, there is a real risk of new countries being affected."
With that in mind, many countries, including the UK, have introduced what are described as "sensible steps" to contain the outbreak including screening and testing air passengers, and monitoring flights from West Africa.
However, doctors acknowledge that the measures might be too late as some people might have travelled unwittingly suffering from the virus while it was incubating. The secretary-general of the International Civil Aviation Organisation, Raymond Benjamin, has already warned that there could be further restrictions on international air travel if it is found that the virus is "hitch-hiking" on passengers and spreading across the world.
Fear, misinformation and superstition have added to the problems. In each of the affected countries, health workers and clinics have come under attack from panic-stricken crowds who blame foreign doctors and nurses for bringing the virus to remote communities.