Transmission of low-density hepatitis C viral particles during sexually transmitted acute resolving infection.

Hepatitis C viruses in the blood of chronically infected patients are heterogeneous in density with the presence of lipoprotein associated viral particles of lower density than conventional virions. If low-density viral particles have been shown to be infectious in animal models it is currently not known whether these particles display the same infectivity for humans. In a case of sexually transmitted acute resolving infection, all isolated NS3 sequences from the acute-phase isolate clustered with a single sequence from the chronic carrier isolate, suggesting bottlenecking during transmission. To determine the density of the transmitted viruses, viral quasispecies from fractions with density below and above 1.055 g/ml were isolated and prepared from the plasma of the chronically infected sexual partner. Interestingly, the three closest sequences to the recipient consensus sequence were isolated from the low-density fraction. These data suggest that low-density viral particles are infectious for humans as they are for chimpanzees and that they can be transmitted during sexual intercourse.