Two genetically distinct
but related variants of the virus have been isolated from patients with
AIDS, HIV-1 and HIV-2.
Each is a non-transforming
retrovirus with specificity for the CD4+ lymphocyte receptor.
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HIV-1 is the most common agent
in the US, Europe and Central Africa.
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HIV-2 causes a similar disease,
but is seen principally in West Africa. (Slower progression)
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There is some antigenic similarity
between HIV-1 and HIV-2, but they are distinct viruses.
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Recently developed screening
test allow testing specifically for HIV-2
The following discussion relates
primarily to HIV-1, but general aspects apply to HIV-2 as well.
Viral
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