BBC report 5 Oct. 2015, "Ebola biggest challenge since AIDS." Includes maps of disease density.
The disease is obtained through close contact with animals- Fruit bats, forest antelope (both items of food) and chimpanzees.
It an be spread by indirect contact, through contaminated environments (How long surfaces, etc., are affected depends on several factors.

A patient who recovers may still be infectious up to seven weeks after recovery, since their blood and secretions still contain the virus.

Cases, although concentrated in Sierra Leone, Guinea and Liberia, extend across Africa west to east, from Senegal to Uganda, including South Sudan, Gabon, Conge, DR Congo, Uganda.
Hopefully, the disease has been contained in Senegal and Nigeria.
Liberia has been most affected, with 2200 deaths up to Oct. 5.
Close contact with dead relatives is a cultural trait in many of the societies, and is a cause of transmission of the disease.