People 18 years of age and older who are infected with HSV and people who are not infected with the virus may be eligible for this study. Participants will have blood drawn to confirm whether or not they have been infected with the virus. The blood sample will also be used to study the genes for the HSV receptor, Fc receptors, cytokines, mannose binding protein and related proteins on the white blood cells. No more than 40 milliliters (8 teaspoons) of blood will be drawn.