Table 1. Infectivity and transmission of WT, ospC mutant, and complemented B. burgdorferi clones in mice and ticks.

		Mice infected/analyzed		Ticks infected/analyzed by IFA or culture
Clone	Infection route	Seroconversion	Reisolation*
B31-A3	Needle inoculation†	7/9	4/9	3/17‡
	Tick bite	5/6	5/6	26/28§
ospC7	Needle inoculation†	0/12	0/12	0/20‡
	Tick bite¶	0/1	0/1	0/1§
ospC7/ospC+4	Needle inoculation†	4/6	4/6	5/27‡
	Tick bite	8/12	8/12	17/30§

^*Two to four tissues were analyzed per mouse.

^†Inoculum of 4 × 10³ organisms i.p. and 1 × 10³ organisms s.c.

^‡Larval ticks.

^§Nymphal ticks.

^¶Larvae fed on four mice injected with ospC7 and were negative for spirochetes by IFA. After the molt, a subset of nymphs were fed on one mouse.