A clinical drug trial is under way in Liberia to determine if a medication could help those suffering from Ebola.

A clinical drug trial is now under way at a major health centre in Liberia's capital to determine if a medication already used to treat other viruses could help those suffering from Ebola.

The drug called brincidofovir is being tested in patients at the ELWA 3 centre operated by Doctors Without Borders, the group said on Tuesday.

Ebola, which has no licensed treatment or cure, has killed more than 8000 people in West Africa over the past year.

"It must be stressed that it is not a miracle cure and it is still not known whether it will help patients survive the virus," the medical charity said in announcing the start of the drug trial this week.

Brincidofovir is an antiviral drug being developed to treat several types of viruses, including one that infects patients undergoing bone marrow transplants.

All new patients confirmed to be Ebola positive by blood test at the charity's ELWA 3 centre will be informed about the trial and can decide whether they would like to participate, the group said.

Brincidofovir is not the only drug being considered for use in treating Ebola. Another drug - ZMapp - healed all 18 monkeys infected with the deadly virus in one recent study.

Experimental doses of ZMapp also were given to several humans who suffered from Ebola before the manufacturer's supply ran out months ago.

A third drug - The TKM-Ebola injection - works by blocking genes that help the Ebola virus reproduce and spread. It has been used in at least one patient and is said to be in limited supply.

Other patients have received blood donations from Ebola survivors who had developed antibodies to the virus.