Under a magnification of 1125X, this photomicrograph of a sample of brain tissue, revealed the presence of a cytomegalic inclusion cell, located outside the lumen of a brain capillary. With its enlarged, darkly-stained nucleus, such cells are also known as owl-eye inclusion cells, and are due to cytomegalic inclusion disease, caused by the cytomegalovirus.
“For most healthy people who acquire cytomegalovirus (CMV) after birth, there are few symptoms and no long-term health consequences. Some people who acquire CMV infection may experience a mononucleosis-like syndrome with prolonged fever and hepatitis. Once a person becomes infected, the virus establishes lifelong latency and may reactivate intermittently. Disease from reactivation of CMV infection rarely occurs unless the person's immune system is suppressed due to therapeutic drugs or disease.”
For more on the topic of cytomegalovirus, see the link below.