There are no vaccines, though some are being tested, along with new drug therapies. The WHO ruled in August that untested drugs can be used to treat patients in light of the scale of the current outbreak.
The experimental drug ZMapp has been used to treat several people who contracted Ebola: Two US aid workers and a Briton have recovered after taking it but a Liberian doctor and a Spanish priest have died.
But the US pharmaceutical company that makes it says it has for now run out of it.
Patients with Ebola frequently become dehydrated so they should drink solutions containing electrolytes or receive intravenous fluids.
MSF says this outbreak comes from the deadliest and most aggressive strain of the virus.
The current outbreak is killing between 50% and 60% of people infected.
It is not known which factors allow some people to recover while most succumb.