Temporal changes of Japanese encephalitits virus in different brain regions of rat

BACKGROUND & OBJECTIVES Japanese encephalitis virus (JEV) infection results in acute encephalitic illness. The affinity of JEV to different regions of brain and temporal changes in viral load have not been studied. This study was conducted to describe localization of JEV to different regions of the brain at different stages of disease in a rat model of Japanese encephalitis (JE). METHODS Twelve days old Wistar rats were inoculated intracerebrally with a dose of 3 x 10⁶ pfu/ml of JEV. After 3, 6, 10 and 20 days post-inoculation, brains were dissected out and different regions of brain (cortex, striatum, thalamus and mid brain) were taken. Motor deficit was assessed by the rota rod and JEV RNA copies were evaluated using real-time PCR assay. RESULTS There was a significant increase in motor deficit in rats inoculated with JEV compared to the controls. JEV RNA copies were present in all studied regions of the brain on days 3, 6 and 10 post-inoculation. Maximum number of JEV RNA copies were present in the mid brain on days 3 and 10 post-inoculation. JEV RNA copies were not detected in any of the brain regions on day 20. INTERPRETATION & CONCLUSIONS This study reports JEV RNA load in different brain regions of rat with higher affinity of JEV virus to thalamus and mid brain compared to other regions.