Early defects in dissemination and colonization, attributed to the disruption of DbpA/B, are not observed in the chronic stages of Lyme borreliosis in immunocompetent mice. Shown are copy numbers of B. burgdorferi flaB DNA per mg tissue (mean ± SEM) in tissues from C3H mice inoculated with B31-ΔdbpBA (white bars) compared to wild-type B31-A3 (black bars) at 14 days, 28 days, and 42 days postinoculation. *, all P values ≤ 0.034.