Morbidity and Virus Load at Different Time Points after i.m. or i.v. Inoculation of SB.

Twelve mice were inoculated with 107 ffu of SB either by i.v. or i.m. injection and monitored for symptoms until mice were euthanized in a still healthy state (2 days post infection), at the onset of weight loss (4 days post infection) and in the progressed symptomatic stage (7 days after i.v. respectively 6 days after i.m. infection). Virus load was assessed for all animals by immunohistochemistry against RV in matched frontal brain sections (stereotaxic coordinates: interaural 2.34 mm, bregma −1.4 mm). Animals in italic typeset were chosen for further analysis.1From ‘−’, no signs of illness, to ‘+++++’, morbid.2From ‘−’, no immunoreactivity against RV RNP, to ‘++++’, many RV RNP immunoreactive neurons and fibers in several areas.