To determine the extent of parenchymal CD163 expression in SIV and SIVE, we utilized a bioquantification software system to quantify parenchymal CD163 positivity in cerebral white matter of non-infected and SIV-infected rhesus macaques, with and without encephalitis, excluding perivascular cuffs and nodular lesions in SIVE. The gene discussed is CD163; the disease is viral encephalitis.