Granular ependymitis. Occurrence in myxovirus infected rodents and prevalence in man.

Intracerebral inoculation of neuropathic and nonneuropathic strains of mumps virus into adult hamsters resulted in an acute focal infection of ependymal cells followed by focal ependymal denuding. Similar lesions followed defective infection with influenza A in both hamsters and mice; when a large amount of influenza A was inoculated, aqueductal stenosis and hydrocephalus developed in some adult animals as a sequela of widespread ependymal cell loss. A survey of 100 consecutive adult human brains showed that 65% had granular ependymitis which had many of the characteristics found in the focal ependymal lesions produced in rodents. These studies suggest that human CNS mumps infections may produce granular ependymitis.