The immune response of big brown bats (Eptesicus fuscus fuscus) maintained at various environmental temperatures to experimental infection with the OCT-541 strain of Japanese B encephalitis virus has been studied. Neither complement-fixation nor hemagglutination-inhibition antibodies could be demonstrated in plasma samples obtained from animals at intervals following single or multiple doses of virus. Specific neutralizing antibodies were demonstrable in approximately 75 percent of the infected bats, reaching detectable levels more rapidly in animals maintained at 37°C than in those kept at 24°C. No evidence of antibody formation was demonstrated in infected animals while maintained for prolonged periods at 8°C. Determinations on bats maintained in the laboratory for 2 to 3 years provided evidence of spontaneously recurrent viremias as well as susceptibility to reinfection with JBE virus, suggesting that the immune response of these animals to arbovirus infection would not repress completely their effectiveness as reservoir hosts.
Presently FAO (UN) Virologist, Near East Animal Health Institute, Cairo, U. A. R.