Human cytomegalovirus (aka Human herpesvirus 5) is a widely spread pathogen (50-80% of all people by age 40), but seldom of consequence in otherwise healthy people.  However, in young children it can lead to mental and physical disabilities from interference with normal brain development.  Researchers at the University of  Pittsburgh Medical Center reported late last year that stem cells are resistant to cytomegalovirus, and that neuron infection occurs during cellular differentiation. Possibly the virus enters the baby through the salivary glands during nursing.  Among other things, this finding suggests that stem cells are the ultimate cellular source of human wellness.   MORE