Subgroups of five SCID mice were inoculated with 105 spirochetes of the clone ΔospC/ospC'/1, ΔospC/ospC'/2, ΔospC/ospA'/1, ΔospC/ospA'/2, ΔospC/ospE'/1, ΔospC/ospE'/2, ΔospC/vlsE'/1, or ΔospC/vlsE'/2, and euthanized a month later. DNA was prepared from heart, joint and skin specimens and analyzed for spirochete flaB and murine actin DNA copies by qPCR. Data are expressed as spirochete numbers per 106 host cells and presented in four groups by combining the subgroups ΔospC/ospC'/1 and ΔospC/ospC'/2, ΔospC/ospA'/1 and ΔospC/ospA'/2, ΔospC/ospE'/1 and ΔospC/ospE'/2, and ΔospC/vlsE'/1 and ΔospC/vlsE'/2.