In addition to passing on the virus through unprotected sexual intercourse, drug addicts often share needles containing blood contaminated with the virus.

A former employee of UB Plasma has said that its directors knew they were selling blood contaminated with H.I.V.

Studies indicate that infection can be transmitted by a much smaller amount of blood contaminated by the hepatitis B virus than by blood with the AIDS virus.

The new test will not exclude all blood contaminated with hepatitis C because it detects the presence of antibodies, the proteins the body forms to fight invading organisms.

In addition, the screening test that eliminates blood contaminated with the AIDS virus has virtually ended the spread of the disease through transfusions.

Judge Torres said "the facts strongly suggest" that the blood contaminated with the AIDS virus was administered to the boy at Children's Hospital.

Extrapolating from these findings, the scientists estimated that 2,800 of the four million Americans who receive transfusions each year, many receiving multiple units, may be receiving blood contaminated with HTLV-1.

Romanian blood products have been found to be one source of blood contaminated with H.I.V. that was distributed by a German company, World Health Organization officials say.

Public awareness of the syndrome increased after it became known in 1992 that blood contaminated with the virus had been given in transfusions to hundreds of hemophiliacs in the mid-1980's.

Was the chauffeur's blood contaminated with lethal quantities of carbon monoxide?