Similar HIV-1 subtype A V3 loop sequences are found in dual HIV-1/HIV-2 and HIV-1-only seropositives in Ghana

Ghana and Ivory Coast are situated between the two major initial foci of the African HIV-1 and HIV-2 epidemics. It is in such countries that dual HIV-1/HIV-2 serological reactivity (dual seropositivity) is most common. The proportion of dual seropositivity has increased in West Africa countries, where HIV-2 was initially the main cause of the epidemic. The diagnosis of dual HIV-1/HIV-2 infections may be complicated, as HIV-2 DNA cannot always be detected and the levels of HIV-2 DNA in dual seropositives may decrease with progression to AIDS. Also, even low levels of HIV-2 antibodies can imply dual infection. The lack of HIV-2 DNA and/or low HIV-2 antibody level may thus be related not only to the diagnostic methods used, but possibly to suppression of HIV-2 by HIV-1.