FIG 1.

Experimental infection of sheep with BTV8wt and BTV8ΔNS4. Three groups of sheep (n = 5 per group) were mock infected or infected with either BTV8wt or BTV8ΔNS4. (Top) Body temperatures (average per group) of experimentally infected sheep. The rectal temperature of sheep is normally between 38.3 and 39.9°C (horizontal lines). (Middle) BTV RNA in blood samples of experimentally infected sheep. Viral RNA was detected by qRT-PCR targeting Seg-5, and the values are expressed as log₁₀ copy number per microgram of total RNA. (Bottom) Box-and-whisker plot representing neutralizing antibodies in experimentally infected sheep at 7, 14, 21, and 28 days postinfection as described in Materials and Methods. PD₅₀, 50% protective dose. **, P < 0.01; ***, P < 0.001 (two-way analysis of variance [ANOVA]; Bonferroni posttests) (gray stars, mock infected versus BTV8wt infected; black stars, BTV8wt infected versus BTV8ΔNS4 infected). The error bars represent standard deviations.