Experimental infection of man with rabbit-virulent Treponema paraluis-cuniculi.

Virulent Treponema paraluis-cuniculi was inoculated intradermally into the arm of a human volunteer and into the shaved backs of 10 rabbits. An identical, but heat-killed, preparation was inoculated into the opposite arm of the volunteer as control. A superficial and transient infection developed in the volunteer, shown by a small zone of erythema that persisted for 24 days. The control preparation caused a smaller zone of erythema that disappeared after five days. A very poor immune response was detected by standard serological tests for syphilis. The inoculated rabbits developed lesions about six days after infection and seroconverted by 84 days. The poor antitreponemal antibody response to T paraluis-cuniculi infection in the volunteer suggests that this naturally attenuated treponeme may not be suitable as a vaccine against infection with t pallidum in humans.