Molecular analysis of human immunodeficiency virus strains associated witha case of criminal transmission of the virus

An investigation was done of the evidence for transmission of human immunod eficiency virus (HIV) from an HIV-positive man to several male and female s ex contacts. Phylogenetic analysis of sequences from the gag and env genes showed a close relationship between the predominant virus strains from the source and 2 contacts. However, the likelihood that a female contact was in fected by the source could not be determined, despite contact tracing indic ating that this may have occurred. One male, shown by contact tracing and m olecular evidence to have been infected by the source, subsequently transmi tted HIV to his female sex partner. HIV sequence from a plasma sample used as a control in the phylogenetic analysis contained env and gag sequences t hat were closely related to those from the source. An epidemiologic link be tween these 2 individuals was subsequently confirmed by contact tracing.