Zaire Ebola Fever Outbreak Traced to Lab Worker

A 36-year-old laboratory worker triggered April’s outbreak of Ebola fever in Zaire although the virus first struck in January, a team of international doctors and scientists said today.

In a letter published in the Lancet medical magazine, they said the outbreak started April 9 when the man was transferred between hospitals in Kikwit, east of the capital Kinshasa. They gave no details about how he contracted Ebola.

The unidentified man was suffering from abdominal swelling that had developed after protracted fever. He suffered severe intra-abdominal hemorrhaging and died five days later.

Medical personnel who cared for the patient either during surgery or on hospital wards rapidly became ill. Seventy percent of “first-generation” cases were hospital workers.

About 10 days later, second-generation cases broke out among the families and friends of the first wave of victims.

“Transmission appears to have been mainly person-to-person through contact with bodily fluids and ritual cleansing of bodies before burial,” the letter said.

The World Health Organization said Thursday that the Ebola death toll in Zaire had risen to 164, but that only a few new cases are expected from people still in the incubation period, and “transmission seems now to be completely halted.”