- Serologic evaluation will be used to assess exposure to syphilis, West Nile Virus, Chagas, cytomegalovirus (CMV), Immunoglobulin G (IgG), hepatitis B, and C, HIV I and II, and human t cell lymphoma virus (HTLV) I/II. Participants may not be hepatitis B or C (+) unless positive due to previous vaccination or positive but has received therapy and is negative for hepatitis B or C by rapid test polymerase chain reaction (RT-PCR). An HIV-I/II(+) and HTLV-1/II (+) participant will be rejected on medical grounds. Participants serologically positive for syphilis, West Nile Virus, Chagas, CMV, are only excluded if they are being treated for active infection.