title: [Human immunodeficiency virus type 2 infection].
abstract: The isolation of a second retrovirus, HIV-2, led to fears that a second AIDS pandemic, similar in scope and magnitude to that caused by HIV-1, might ensue. However, the peculiar biologic properties of HIV-2, namely the lower transmissibility of this virus through both sexual and vertical routes, contributed to a more regionalized distribution of the virus, which became endemic in West Africa. HIV-2 is genetically more closely related to SIV than to HIV-1. When it comes to clinical disease, the spectrum of opportunistic infections and tumors (except for Kaposi sarcoma) are similar to that observed with HIV-1. Controlled longitudinal studies suggest that the rate of progression to advanced HIV related disease and mortality are far lower for HIV-2 than for HIV-1. Understanding how, immunologically and virologically, HIV-2 behaves differently from HIV-1 may provide some insight into the mechanisms governing HIV-1 pathogenesis.
authors.affiliation: Serviço de Doenças Infecciosas, Hospital Egas Moniz, Lisboa.
authors.forename: K
authors.initials: K
authors.lastname: Mansinho
mesh_terms: D015658:HIV Infections / Q000175:diagnosis / Q000453:epidemiology / Q000635:transmission / Q000821:virology; D015498:HIV-2 / Q000235:genetics; D006801:Humans