A new drug that is used to treat the Ebola virus has moved one step further after American scientists were granted permission to proceed with human trials.

Clinical trials have been approved after the new drug was found to be effective on monkeys.

Ebola is fatal in 90% of human cases, but is 100% fatal in all ape cases.

About 1,200 people have died of the disease since 1976, but there are fears that it could be used as a biological weapon by terrorists.

Ebola is transferred through body fluids. Symptoms include nausea, vomiting, internal bleeding and organ failure eventually leading to death.

The newest tests showed that the new drug cured the virus in 60% of rhesus monkeys.

It was 100% effective in treating the related Marburg virus found in cynomolgus monkeys.

The FDA has now granted permission for trials involving a small group of volunteering humans.

The high mortality rate of the disease has fueled fears that it could be used for bio terrorism and funding into reasearch for a treatment was increased in the US after the 9/11 attacks.

The new treatment is being developed jointly by the US Army Medical Research Institute of Infectious Diseases and private company AVI BioPharma.

Scientists caution, however, that despite the apparent progress, a full vaccine will take time to develop with extensive trials an assessments needed.