Human herpesvirus-6 entry into the central nervous system through the olfactory pathway   Abstract  Viruses have been implicated in the development of neurodegenerative  diseases, such as Alzheimer's, Parkinson’s, and multiple sclerosis.  Human herpesvirus-6 (HHV-6) is a neurotropic virus that has been  associated with a wide variety of neurologic disorders, including  encephalitis, mesial temporal lobe epilepsy, and multiple sclerosis.  Currently, the route of HHV-6 entry into the CNS is unknown. Using  autopsy specimens, we found that the frequency of HHV-6 DNA in the  olfactory bulb/tract region was among the highest in the brain regions  examined. Given this finding, we investigated whether HHV-6 may infect  the CNS via the olfactory pathway. HHV-6 DNA was detected in a total of  52 of 126 (41.3%) nasal mucous samples, showing the nasal cavity is a  reservoir for HHV-6. Furthermore, specialized olfactory-ensheathing  glial cells located in the nasal cavity were demonstrated ...