Modification of Venezuelan Encephalitis Virus Infection in Mice by X Radiation.
ARMY MEDICAL RESEARCH INST OF INFECTIOUS DISEASES FREDERICK MD
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A highly virulent strain of Venezuelan encephalitis VE virus produced less severe histopathologic lesions in brain tissues of mice that had been previously exposed to sublethal total-body x-irradiation than it caused in nonirradiated mice. Prior exposure to 600 R x-irradiation virtually eliminated the lesions of vasculitis and encephalitis that were found in the nonirradiated-infected control mice. Mean peak brain lesion scores generally decreased as radiation exposure dose increased. Irradiation of mice prior to infection often decreased median time to death and severity of pathologic lesions in brain tissues without significantly altering ultimate host survival. The inflammatory response does not appear to have a significant role in the clearance of this virus from the brain. The immune response contributes very little to total mortality from VE virus encephalitis. Mortality is caused by the direct cytocidal effects of VE virus replication. Nonimmune mechanisms are apparently of major importance in the pathogenesis of virulent VE virus infections in mice, as indicated by the failure of immunosuppression to reduce mortality. Author
- Medicine and Medical Research