HIV 
(āch′ī-vē)
(āch′ī-vē)n.
A retrovirus of the genus Lentivirus that causes AIDS by infecting helper T cells of the immune system. The most common serotype, HIV-1, is distributed worldwide, while HIV-2 is primarily confined to West Africa.
[H(UMAN) I(MMUNODEFICIENCY) V(IRUS).]
HIV