Characteristic Ultrastructural Changes in Organs of Newborn Mice Infected with EMC Virus 1

Summary

A specific ultrastructural cyto-pathologic response to EMC viral infection was observed in various organs of newborn mice infected with EMC virus. This cyto-pathology is characterized by intracellular proliferation of membrane material with formation of membrane-vesicle complexes, margination of nuclear chromatin, dilatation of rough endoplasmic reticulum, accumulation of cytoplasmic and unidentifiable granular material within membrane-bound cytoplasmic vesicles, and inflammatory infiltration. That the vesicle-bound granules may represent forms of viral materials during the replicative stage is suggested. A high incidence of viral crystals in association with this cytopathology was demonstrated. This host cell-virus interaction is similar to cytopathic changes observed in infections with other picornaviruses. We have designated this intracellular necrosis as “cytonecrosis” and when it is produced by viruses as “virocytonecrosis.”