Canadian and American researchers are reporting a discovery in fighting the diseases caused by the deadly Ebola and Marburg viruses.

They've developed two vaccines that protected monkeys from the viruses, according to a study published in this month's online edition of the journal Nature Medicine.

While it's a promising discovery, a human vaccine could still be at least five years away, said Steven Jones, one of the Canadian scientists involved in the study.

Dr. Steven Jones

The world's largest known outbreak of Marburg virus is blamed for killing 335 people in Angola since last fall.

For humans, there is no vaccine or treatment for either disease, which cause hemorrhagic fevers that can be fatal within a week.

The new vaccines were 100 per cent effective in protecting 12 macaque monkeys against infection from the two viruses, Jones said.

Dr. Jones works on the vaccines.

Researchers at Canada's National Microbiology Laboratory in Winnipeg collaborated with the U.S. military on the vaccines.

Scientists at the U.S. Army Medical Research Institute of Infectious Diseases in Maryland injected the monkeys with the vaccines, and then 28 days later with the viruses.

Last year, Dutch biotechnology firm Crucell announced an Ebola vaccine it developed successfully protected monkeys during trial tests.

Dr. Jay Keystone, an infectious disease expert in Toronto, welcomes the research. But he says there are still many questions.

"If these viruses are ever weaponized that would be a major problem, and that's where the vaccine may be required in a greater context and large numbers of individuals immunized."

Jones says he's not worried about getting the human vaccines manufactured once they're developed. He says there is a commercial market for them because of their potential as a defence against bio-terrorism.