Reports that a Russian military institute has discovered the first antibody against the deadly Ebola virus were confirmed by a Defense Ministry spokesman Friday.


"It is true," said ministry spokesman Ivan Skrylnik. "It is made out of horse blood."


But while the drug's distributors claim that it is "almost 100 percent effective" against Ebola, the World Health Organization, or WHO, remains skeptical.


In a telephone interview, Jim Le Duc, head of the WHO special virus group, said that while experiments of the drug on rodents had been very promising, a number of monkeys had died after taking it.


"The limited quantities of the product indicated that is was not as valuable as we had hoped," Le Duc said. "It's too early to tell how good this will be on humans."


After two years of research, the Defense Ministry's Scientific Research Institute of Microbiology discovered the drug last summer and sold it to the WHO after an Ebola outbreak in Zaire last May that killed more than 150 people.


And according to Yevgeny Smirnov, commercial director of Epidbiomed, which distributed the drug to the World Health Organization, the antibody marks a breakthrough for Russian medical science.


"The Americans were working on this too," Smirnov said.


"But they didn't have results like these. There aren't very many competitive formulae in this area, so we're very happy for the team that found this," he said.


A highly contagious disease, Ebola has been more than 80 percent fatal, causing its victims to bleed internally and sometimes through pores and bodily orifices, Le Duc said.


Named after a river in northern Zaire, it belongs to a class of organisms which destroy the linings of capillaries and blood vessels, prompting fluids to drain from the circulatory system.


Along with rabies and HIV, it is considered to be one of the world's deadliest viruses.