PROJECT SUMMARY/ABSTRACT: Continuous testing for certain viruses that can compromise HIV research results, is essential in any SPF Program used for this purpose. The CPRC-SPF colony is free and systematically assayed for Simian immunodeficiency virus (SIV), Type D Simian retrovirus (SRV-D) and Simian T-lymphotropic virus (STLV-1). The colony is also free of Herpes B virus, which represents an occupational health risk for the personnel handling the animals. The primary purpose of the virology testing arm of CPRC-SPF breeding program is to assure that its Indian-origin rhesus macaque colony, supporting NIH-sponsored research specially on HIV/AIDS, is free of the above- mentioned viruses. An advantage of this program is that it has been closed to external individuals since 2016. Certainly, this aspect substantially decreases the risks of the re-introduction of any of the four tested viruses from an external source. The specific aim of the Viral Testing Core is: Sustain the implementation of the reliable viral- testing algorithm to continue producing high quality SPF animals with a well-defined virological status in support of PHS-NIH sponsored biomedical research, especially HIV/AIDS studies.