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transmission of Toxoplasma

John Bohmfalk jbohmfal at hastings.edu
Thu Feb 24 11:01:18 EST 2000

The other day, James Mahaffy  posted a question concerning blood bank
screening for parasitic diseases, specifically Toxoplasma.

I checked out the Red Cross web site, and couldn't find what I was
looking for, so I emailed a request for information to them.  Yesterday,
I received a very nice response which I have copied below.  Sorry it is
so long.

John Bohmfalk
Asst. Prof. of Biology
Hastings College
jbohmfalk at hastings.edu

In reply to your query, the American Red Cross tests each pint of blood
8 transfusion-transmissible infectious diseases (HIV/AIDS, hepatitis C,
hepatitis B, T-cell lymphoma-leukemia, tropical spastic parpaparsis and
syphilis). Specifically, we test for hepatitis C, hepatitis B surface
antigen, hepatitis B core antibody, alanine transferase, anti-HIV, anti
HIV2, anti-HTLV-I, anti-HTLV-II, HIV p-24 and anti-syphilis on all
blood.  Please note that T-cell lymphoma-leukemia and tropical spastic
parpaparsis may not develop until 30-40 years after infection.  It only
happens in about 3% of people who carry the virus.

On March 1, 1999, the American Red Cross became the first U.S. blood
organization to implement a Nucleic Acid Testing (NAT) study on pools of

individual donor samples.  This process is different from traditional
testing because it looks for the actual presence of Human
Virus (HIV) and hepatitis C virus (HCV).  Most current tests detect the
presence of antibodies, which is the body's response to an infection and

which take time to develop. NAT provides an opportunity to further
the safety of the blood supply by reducing the "window period", which is
time between exposure to a virus to the time current, licensed tests are

able to detect antibodies to the virus. The FDA has not approved the
however, the Red Cross has been permitted by the agency to implement the

study under an Investigational New Drug (IND) protocol. This new testing

also gives Red Cross the ability to help the American people by alerting

donors to see their physician seeking counseling and possible treatment
an earlier period following potential infection than would have been
possible using current licensed serologic testing. ARC is continuing to
enhance the NAT systems until all routine blood components are released
after NAT testing is completed.   In addition, NAT may be expanded to
for additional viruses.  We are hopeful that NAT technology will
revolutionize the way blood centers conduct testing in the future.

We hope this information is helpful.  Again, thank you for writing to


Biomedical Services
Biomedical Headquarters


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