HORIZONTAL AND VERTICAL TRANSMISSION OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 DUAL INFECTIONS CAUSED BY VIRUSES OF SUBTYPE-B AND SUBTYPE-C

This article describes a case of horizontal (heterosexual) and subsequ ent vertical (mother to infant) transmission of 2 human immunodeficien cy viruses type 1 (HIV-1) subtypes. Dual infection in a husband, his w ife, and their child was initially detected by use of a restriction fr agment length polymorphism assay of the proviral protease in periphera l blood mononuclear cells. The simultaneous presence of highly similar sets of HIV-1 subtypes B and C infecting the 3 family members was con firmed by DNA sequence analysis of pol, gag, and env genes. These data , together with available epidemiologic information, may indicate that the husband's high-risk sexual behavior was the source of dual infect ions. Because his wife did not report such activities, it was likely t hat he passed HIV-1 strains to his spouse, who subsequently transmitte d them to their child.