Experimental inoculation of BALB C mice with Ebola virus

Abstract

Ebola virus is the causative agent of a severe hemorrhagic fever with fatality rates in humans approaching 90% with the Zaire species of the virus. Previous attempts at producing an experimental mouse model for Ebola Zaire have had limited success. Until recently, Ebola Zaire has not been shown to be lethal in adult BALB/c mice but has been lethal in suckling BALB/c mice. We performed blind passages in suckling, aged suckling and adult BALB/c mice with a low passage strain of Ebola Zaire. Suckling BALB/c and aged suckling BALB/c mice were susceptible to Ebola infection while adult BALB/c mice showed no susceptibility to Ebola infection. Antigen detection by ELISA indicated virus replication throughout the blind passages in all mouse groups. Plaque titrations in Vero E6 cells of passaged tissue suspensions were limited in success with only 8 of 43 suspesions producing plaques. Antigen detection by ELISA titers showed no correlation with the ability of the passaged suspension to produce viable plaques. The reason for the inability to produce viable plaques is unknown at this time. A more thorough evaluation of Ebola Zaire virus replication in mice is needed to fully understand Ebola Zaire virus replication in BALB/c mice.