Figure 6.

Cache Valley Virus (CVV) infection produces high viral loads and is lethal in CD-1 suckling mice. Two-day-old suckling mice (CVV 4B n = 28, CVV W08491 n = 23, PBS n = 15) were challenged intracranially with 10⁴ plaque forming units (PFU) and (a) survival and (b) weight change measured daily for 14 days post infection (DPI). (c) Virus titers were measured in brain sections harvested on 3 and 5 DPI. Each data point plotted represents the mean values, and error bars indicate standard deviation. The limit of detection (LOD) is indicated with a dotted line. Statistical significance among groups was analysed by logrank (Mantel-Cox) test in (a) a mixed effects analysis with a Dunnett's multiple comparison test in (b,c) Statistical significance is denoted by * (p < 0.05). Brain sections were analysed for histopathological effects after H&E staining 3 and 5 DPI. Sections were evaluated for degree of necrosis characterized by neuropil hyalinization and vacuolation (asterisk) as well as shrinkage of cells and condensation of nuclei (arrows). Sections were also evaluated for degree of inflammation as well which was minimal and mostly characterized by rare infiltration by neutrophils (not shown), on (d,e,f) 3 DPI and (g,h,i) 5 DPI. Images were captured at 40x magnification.