Marburg Virus Fingered in Killer Outbreak

The Marburg virus is to blame for the deadly outbreak of hemorrhagic fever in the Democratic Republic of Congo, according to the World Health Organization (WHO). The virus has been isolated from one victim of the epidemic, which has sickened 76 people since January, killing 52.

When the outbreak began, health workers first feared the culprit was Ebola virus, which killed hundreds of people in the same country (then called Zaire) in 1995. But the disease did not seem to spread as easily as Ebola, and WHO announced Wednesday that serological tests had ruled out that virus. On Thursday officials announced that researchers at the National Institute for Virology at the University of Witwatersrand in Johannesburg, South Africa, had detected Marburg--a cousin of Ebola--in a blood sample from a district medical officer who died on 23 April.

However, no one is yet sure if the Marburg virus is responsible for all of the illnesses. Samples from four other suspected victims, who are still hospitalized but have not yet shown signs of hemorrhaging, have so far tested negative for both Ebola and Marburg, says Ray Arthur, a medical officer in the WHO department of communicable diseases surveillance and response in Geneva.

A team of epidemiologists and viral experts from the WHO and the U.S. Centers for Disease Control and Prevention in Atlanta will attempt to reach the affected area, which is remote and plagued by civil war, early next week to collect more samples and look for the source of the outbreak. There is no effective treatment or vaccine for Marburg, whose symptoms include fever, diarrhea, vomiting, and massive hemorrhaging.

Arthur said the outbreak may provide new clues to the natural reservoir of the virus. Two of the three previous outbreaks of Marburg in the wild have been traced to people who spent time in caves, and scientists have suspected that bats or cave-dwelling rats might harbor the virus. Many victims of the current outbreak were illegal gold miners who had spent time in caves.