The pathogenesis of infection in mouse brain by Mount Elgon bat virus

Mount Elgon bat virus given intracerebrally readily killed mice up to 12 days of age (1 to 4 p.f.u/LD50). Virus in doses of 10 to 10(6) p.f.u. killed 40 to 80% of weanling mice of both sexes and up to 20% of adult females and 40 to 80% of adult males. Clearance of brain infectivity in the resistant mice coincided with the appearance of circulating virus neutralizing antibody which occurred earliest in the adult female mice. Immunosuppression of adult mice with cyclophosphamide resulted in the death of all the virus-inoculated mice of both sexes. Virus in these mice reached tenfold higher titres and their brains contained 30- to 60-fold more interferon than the brains of infected mice not given cyclophosphamide. Interferon was apparently without effect on the outcome of infection in the brains of resistant mice and its synthesis reflected the extent of virus growth.