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Researchers Say Promising Experimental Treatment  of Ebola-infected Monkey Could be Successful in Humans - 2003-12-12

U.S. researchers have used a novel approach to save the lives of monkeys infected with the deadly Ebola virus. The journal that published the results says they are an important step towards a possible treatment for the disease, which is fatal in up to 90 percent of people infected.

Ebola virus, first identified in a 1976 outbreak in the former Zaire, is one of the most lethal diseases.

It is also one of the most gruesome. Many victims bleed from the eyes, nose, and mouth. But bleeding occurs in less than half of Ebola cases. The most serious aspect of the disease is excessive blood clotting. Scientists believe the virus increases the production of a substance that promotes clotting. As the blood becomes thicker, it blocks blood vessels, leading to shock and the failure of multiple organs.

Now, researchers have attacked the problem by preventing blood coagulation in a small group of Ebola-stricken monkeys, saving some of them from certain death.

"The main value of this study is that it shows there is a possibility for treating this disease," says virus expert Thomas Geisbert of the U.S. Army Medical Research Institute of Infectious Diseases near Washington. "This certainly gives us potential because we have a lot of different strategies to protect rodents very successfully against Ebola - antiviral drugs and different treatments that protect rodents. But when we employ these same strategies in monkeys, they have not quite panned out [worked] as well, which is why we were excited about this, because it actually did protect monkeys."

In the experiment, Mr. Geisbert and his colleagues injected 12 monkeys with Ebola virus. Nine of the animals then received a protein that inhibits blood clotting.

As they report in the medical journal The Lancet [13 December edition], all untreated monkeys died, but three of the nine treated monkeys survived. Mr. Geisbert points out that with a disease that kills nearly all monkeys who get it, a 33 percent survival rate is welcome. "These animals became infected, they got sick, but they did not get as sick as the monkeys that died or were not treated," he said.

Even the six treated monkeys who died lived four days longer than they would have without the anti-blood clotting drug.

The researchers say they hope the treatment can be more successful in people because Ebola does not kill humans at the same high rate as it does monkeys and progresses more slowly.

There are no effective drugs to fight the Ebola virus in people, but if there ever are, Mr. Geisbert envisions using them in combination with the blood thinning drug to increase the survival rate. "We're hoping that maybe by augmenting this particular strategy with other strategies, we can even improve a little bit better," he said.