Microbiologist Pat Leman, does various culture tests in an isolation laboratory at the National Institute for Virology in Johannesburg Thursday May 6 1999. Tests on tissue samples indicate that an outbreak of hemorrhagic fever that has killed 63 people in northeastern Congo is probably not the feared Ebola virus, but was likely caused by the Marburg virus, the World Health Organization said Thursday, March 6, 1999. (AP Photo/Denis Farrell)
A microbiologist at the National Institute for Communicable Diseases in Johannesburg, South Africa, tests a tissue sample for the Marburg virus.

First West African case of deadly Marburg virus detected in Guinea