At least one of the following: Exposure risk to HIV, KSHV, or HPV; HIV seropositive; KSHV seropositive; EBV seropositive; HTLV-1 seropositive; Malignancy, Castleman's disease, or skin lesions with appearance of Kaposi's sarcoma; Cervical or anal intraepithelial lesion; Clinical condition reported or hypothesized to be associated with xenotropic murine leukemia virus-relted virus (XMRV)