Table 2. Serological and physical markers of testicular infection in RIT rabbits.

	Donor animal*	Recipient animal†	Test
			Seroconversion	Orchitis	Darkfield
Control	Ct1	R-Ct1	+ (Day 31)	+ (Day 39)	+
	Ct2	R-Ct2	+ (Day 31)	+ (Day 42)	+
Immunized	Im1	R-Im1	−	−	−
	Im2	R-Im2	−	−	−
	Im3	R-Im3	+ (Day 73)	−	Not performed

The symbol ‘+' indicates positive seroconversion (reactive VDRL (≥1:1) and FTA-ABS (≥3+)). The symbol ‘−' indicates negative seroconversion (nonreactive/weakly reactive VDRL and FTA-ABS (≤2+)).

^*Rabbits dermally infected with T. pallidum.

^†Rabbits that received testicular injections of popliteal lymph nodes from T. pallidum-challenged animals.