qRT-PCR analysis of rpoS transcription in ticks and in mouse tissues. A, flat (uninfected) larvae, fed larvae, intermolt larvae, and fed nymphs during transmission phase were collected at 24-, 48-, and 72-h post-feeding. TT: tick transmission. B, mouse tissues of skin (S) heart (H), and bladder (B) were collected at various numbers of days (inset) after infection. The values represent the average copy number normalized per 100 copies of B. burgdorferi flaB transcripts.