[Pathogenicity of the Lassa virus for laboratory mice].

Pathogenicity for randombred and inbred mice of various age groups of the standard Lassa virus and the virus enriched with defective interfering particles (DIP) was studied. The standard Lassa virus inoculated intracerebrally caused 100% death of C3H/Sn mice aged up to 4 weeks and 60%-70% death of randombred white mice aged 3-4 weeks. BALB/C mice were found to be nonsusceptible to the virus, and its lethality for C57BL/6 and AKR mice varied within the range of 30%-60%. Lassa virus enriched with DIP caused no death of the susceptible animals and showed poor protective activity against the standard virus.