Experimental transmission of hepatitis B virus by semen and saliva.

The ability of human semen and saliva to transmit hepatitis B virus (HBV) by parenteral and nonparenteral routes was studied. Semen, donated by a hepatitis B surface antigen (HBsAg)- and hepatitis B e antigen (HBeAg)-positive carrier, was administered to one gibbon by subcutaneous inoculation and to another by intravaginal instillation. Both developed HBsAg, followed by the development of antibody to HBsAg (anti-HBs) and antibody to hepatitis B core antigen (anti-HBc). Saliva from two donors who were HBsAg- and HBeAg-positive was pooled and administered subcutaneously to two gibbons and orally to five others. The animals inoculated subcutaneously developed HBsAg followed by anti-HBs, but none of the gibbons exposed orally developed evidence of HBV infection. Thus, semen and saliva of HBsAg carriers can be infectious, and venereal transmission of HBV by semen can occur. Transmission of HBV in saliva can also occur through breaks in the skin, but experimental transmission of HBV by saliva administered orally has not been accomplished.