HIV/AIDS in Laboratory Workers Infected HTLV-IIIB

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surveillance range from 600 to 1200 CD4 cells/mm3 in healthy individuals. The virus with
which F-1 is infected has six novel amino acid substitutions in the major neutralizing region
of the envelope compared to the strain that the worker was using in the laboratory, a sign
that the virus is changing over time.
The worker known as R-2 became infected by a puncture wound in the hand. R-2
was diagnosed with pneumocystis pneumonia 68 months after testing positive for infection.
At 83 months after diagnosis, R-2 has a CD4 count of fewer than 50 cells/mm3 and is
receiving anti-viral therapy. The virus has only three novel amino acid substitutions in the
major neutralizing region of the envelope compared to the virus grown in the laboratory
where R-2 worked.
The third worker, known as S-3, is the most recent to become infected, after
accidental exposure to concentrated virus on the facial skin and mucous membranes. S-3 is
clinically stable with CD4 counts between 200 and 500 cells/mm3 and is receiving anti-viral
drug treatment 25 months after testing positive for infection. The latest test of the virus,
completed a few months after infection, showed no changes in the amino acid sequence of
the neutralizing region of the envelope from the virus being grown in the laboratory.