The primary purpose of the Yerkes Viral Testing Core is to provide accurate, rapid, and cost-effective serological and molecular viral diagnostic testing in support of the Specific Pathogen Free (SPF) colony at the Yerkes National Primate Research Center. The Core employs a pipeline of diagnostic screens and tests which provide definitive diagnoses for the presence of infection by the four viruses that constitute the standard panel of viruses that are screened for by the NIH Office of Research Infrastructure Programs (ORIP)-supported SPF macaque colonies: Simian Immunodeficiency Virus (SIV), Simian T Lymphotropic Virus (STLV), Simian type D retroviruses (SRV), and Macacine herpesvirus 1 (B-virus). Testing for these viruses in the Yerkes SPF colony has been ongoing for 16 years, and the SPF colony has been free of any of these 4 NHP viruses since 2013. Over the past funding period, the Core has increased its self-sufficiency and reduced turnover time in reporting virological results critical for making colony management and animal assignment decisions by establishing an in-house quantitative real-time PCR for the detection of Simian type D retrovirus (SRV) in rhesus macaques. Previously, run on a fee-for-service basis at the California National Primate Research Center, an in-house assay has significantly reduced both the cost and the turnaround time for the confirmation of SRV infection in both SPF and non-SPF rhesus macaques at Yerkes. Additionally, the Viral Testing Core has undergone a review of its Multiple Fluorescent Immunoassay (MFIA) thresholds for positivity. The Core has also implement SARS-CoV-2 screening to ensure the health of the rhesus macaques and the animal resources staff as well as to prevent any confounding complications that SARS-CoV-2 infection may have for AIDS research. During the next funding period, the Viral Testing Core will continue to provide state-of-the-art viral diagnostic services for the SPF breeding colony at Yerkes. Specifically, the Core will continue to develop virus specific beads to increase the specificity of its MFIA screen. These beads will further enhance the efficiency of its diagnostic pipeline. The Core will also add MFIA beads for non-SPF pathogens such as adeno-associated viruses, several flaviviruses, and Trypansoma cruzi. Finally, the Core will continue to screen the SPF colony for SARS-CoV-2 through both targeted swabbing of sick animals as well as fecal screening. The implementation of these tests will be critical (1) for the Yerkes Virology Core to provide cost effective, efficient, and rapid SPF viral testing solutions, (2) for the ability of colony managers to make assignment and husbandry decisions, and, most importantly, (3) for the success of AIDS researchers using nonhuman primates at Yerkes.