Table 2.

Viremia in 6- to 7-day-old CD1 mice after SC infection with WT or mutant CHIKV strain LR or vaccine strain 181/25

Virus straina	Day 2 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
LR	3/3	2.9 ± 0.6	1/3	1.3 ± 0.6
LR/nsP1	2/2	2.2 ± 0.2	0/2	≤ 0.9
LR/6K	3/3	5.0 ± 0.2	3/3	2.7 ± 0.8
LR/E1	3/3	2.5 ± 0.5	0/3	≤ 0.9
LR/E2-12	2/3	2.0 ± 1.1	0/3	≤ 0.9
LR/E2-82	1/2	1.6 ± 1.0	1/2	1.5 ± 0.8
181/25	0/2	≤ 0.9	0/2	≤ 0.9

^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.