Mononuclear cells in Japanese encephalitis virus infection: changes in cells counts and specific fluorescence

Progressive reduction in blood cell counts was observed in mice inoculated intracerebrally (ic) with Japanese encephalitis (JE) virus. No changes were observed in the blood cell counts of mice inoculated intraperitoneally (ip). Reduction in cell counts after a transient rise was noticed in lymph nodes of mice inoculated by either route but the cell counts returned to normal in lymph nodes of ip inoculated mice by the 8th day post inoculation (p.i.). JE virus antigen was demonstrated by immunofluorescence in mononuclear cells from the blood, spleen and lymph nodes starting from the 3rd and 4th day p.i. in mice inoculated ic and ip, respectively. The number of fluorescent cells increased as the infection progressed. The number of fluorescent spleen cells uas higher in ip than in ic inoculated mice. Live virus could only occasionally be demonstrated in the cells.