Researchers Discover How Ebola Virus Bleeds Victims

WASHINGTON —  Researchers have identified the portion of the Ebola virus that causes massive bleeding, the frightening hallmark of the deadly disease that has begun appearing periodically in Africa.

Although Ebola is not common or widespread, it has received much attention since first being reported in 1976 because of the fear generated by the heavy bleeding and the disease’s 90% death rate.

Researchers studying Ebola at the National Institutes of Health found a sugar-containing molecule called glycoprotein sticking out from the surface of the virus.

In test-tube experiments, they discovered a portion of this protein caused it to destroy the endothelial cells that line blood vessels, and by attacking them the protein caused the vessels to leak, the researchers said.

The team, led by Zhi-Yong Yang and Dr. Gary Nabel of the NIH Vaccine Research Center in Bethesda, Md., reported their findings in the August issue of the journal Nature Medicine, published Tuesday. The study results were released Sunday.

No vaccine or specific treatment exists for Ebola, but the researchers’ finding may help point the way toward development of new drugs or vaccines aimed at reducing or preventing the disease.

So far, Ebola generally has struck in remote regions of Africa. The outbreaks included one in 1995 in Zaire that claimed 245 lives.

The virus is named for the river flowing through the region where it first appeared.

Strains of Ebola found in Zaire, Sudan and the Ivory Coast have been fatal to humans. A separate strain affects monkeys.

The researchers studying glycoprotein found that the part of the protein that becomes modified by sugars is toxic to cells infected by the virus. When they made forms of the protein that lacked the sugars, the protein no longer destroyed blood vessels.