HIV-2 is a retrovirus that is distinct from but related to HIV-1. It is found primarily in West Africa and in countries with large populations of West African immigrants. Although HIV-2 is less pathogenic than HIV-1 and most patients with HIV-2 do not have progressive disease, it is similar to HIV-1 in that it, too, can lead to immunosuppression and AIDS. It is important to distinguish between the two viruses because some antiretroviral agents that are effective against HIV-1 should not be used for HIV-2.
Clinicians in New York City should consider HIV-2 in the differential diagnosis of any patient from a West African or endemic country who presents for HIV testing and/or has signs and symptoms of unexplained immunodeficiency with an undetectable HIV-1 viral load. The diagnostic algorithm currently in use by all public and commercial laboratories distinguishes between infection with HIV-1 and HIV-2. HIV-2 viral load testing is available through New York State Wadsworth Laboratory.