Human immunodeficiency virus type 1 shedding pattern in semen correlates with the compartmentalization of viral quasi species between blood and semen

High levels of human immunodeficiency virus (HIV) type 1 have been detected in semen at all stages of disease. However, it is not clear whether HIV-1 is shed in semen continuously or intermittently. In a prospective longitudi nal study viral RNA was measured weekly for 10 weeks in semen and blood of HIV-seropositive subjects, Results showed three different patterns of HIV-1 shedding in semen: none (28%), continuous (28%), and intermittent (44%). I n contrast, there was no change in blood plasma virus load during the study period, Phylogenetic analysis of the envelope sequences of HIV-1 RNA in se men and blood revealed distinct virus populations in semen and blood of int ermittent shedders but similar virus populations in the semen and blood of continuous shedder. These results indicate for the first time that HIV-1 is shed primarily in an intermittent manner and that shedding patterns of HIV -1 in semen are related to compartmentalization of HIV-1 between semen and blood.