Table 5.

Viremia in 5- to 6-day-old CD1 mice after SC infection with WT or mutant CHIKV strain LR or vaccine strain 181/25

Virus straina	Day 1 postinfection		Day 2 postinfection		Day 3 postinfection		Day 4 postinfection
	No. of animals positive/total no. inoculated	Mean titerb of positive animals ± SD	No. of animals positive/total no. inoculated	Mean titerb of positive animals ± SD	No. of animals positive/total no. inoculated	Mean titerb of positive animals ± SD	No. of animals positive/total no. inoculated	Mean titerb of positive animals ± SD
LR	3/4	3.3 ± 2.0	4/4	3.7 ± 0.9	4/4	2.6 ± 1.0	2/4	2.2 ± 1.6
LR/4x	4/4	4.1 ± 1.0	4/4	3.2 ± 0.4	4/4	3.7 ± 1.5	2/4	1.9 ± 1.2
181/25	3/3	4.3 ± 0.2	1/3	1.5 ± 1.0	0/3	≤ 0.9	1/3	1.5 ± 1.0

^aSee Fig. 1b for strain designations.

^bTiters are in log₁₀ PFU/ml of serum, and the limit of detection of the assay was 0.9 log₁₀ PFU/ml of serum.