title: Simultaneous seropositivity to HIV-1 and HIV-2 in Italian drug abusers.
mesh_terms: D006679:HIV Seropositivity / Q000175:diagnosis*; D006801:Humans; D007558:Italy; D019966:Substance-Related Disorders; D014759:Viral Envelope Proteins / Q000302:isolation & purification*
chemical_list: D014759:Viral Envelope Proteins