Many apartment dwellers have heard the thump of one shoe hitting the
floor above them; they may then get tense awaiting the second. In the
blood dilemma, no one knows how many deadly shoes may still hit.

The AIDS virus was designated HIV, but some experts now call it HIV-1.
Why? Because they found another virus of the AIDS type (HIV-2). It can
cause AIDS symptoms and is widespread in some areas. Moreover, it "is
not consistently detected by the AIDS tests now in use here," reports
The New York Times. (June 27, 1989) "The new findings . . . make it
more difficult for blood banks to be sure a donation is safe."

Or what of distant relatives to the AIDS virus? A presidential
commission (U.S.A.) said that one such virus "is believed to be the
cause of adult T-cell leukemia/lymphoma and a severe neurological
disease." This virus is already in the blood donor population and can
be spread in blood. People have a right to wonder, 'How effective is
the blood-bank screening for such other viruses?'

Really, only time will tell how many blood-borne viruses are lurking
in the blood supply. "The unknown may be more cause for concern than
the known," writes Dr. Harold T. Meryman. "Transmissible viruses with
incubation times measured in many years will be difficult to associate
with transfusions and even more difficult to detect. The HTLV group is
surely only the first of these to surface." (Transfusion Medicine
Reviews, July 1989) "As if the AIDS epidemic were not misery enough, .
. . a number of newly proposed or described risks of transfusion have
drawn attention during the 1980's. It does not require great
imagination to predict that other serious viral diseases exist and are
transmitted by homologous transfusions."—Limiting Homologous Exposure:
Alternative Strategies, 1989.

So many "shoes" have already dropped that the Centers for Disease
Control recommends "universal precautions." That is, 'health-care
workers should assume that all patients are infectious for HIV and
other blood-borne pathogens.' With good reason, health-care workers
and members of the public are reassessing their view of blood.