The penetration of normal mucous membranes of the rabbit by Treponema pallidum

Abstract

The fact may be recorded that highly virulent strains of Treponema pallidum are capable of penetrating some portion of the genital mucosa of normal rabbits and setting up an infection without necessarily producing the first gross lesion at the portal of entry. This fact was recently determined in 9 rabbits and with two highly virulent strains of Treponema pallidum. The experimental method employed was as follows: The sheath of the animal was drawn forward to form a pouch into which was instilled 0.05 c.c. of a testicular emulsion rich in spirochetes. About 30 seconds were allowed for the emulsion to spread before releasing the sheath. Most of the fluid then ran out and between 0.04 and 0.05 c.c. could be recovered showing that only a thin film of the emulsion was retained. Infection was first indicated by enlargement and induration of the inguinal lymphnodes and later by the development of a general lymphadenitis with syphilitic lesions in other parts of the body. All animals thus far inoculated by this method have become infected. In some of them, enlargement and induration of the inguinal nodes was clearly recognizable within 24 hours after the application of the emulsion. Thus far (5 weeks) only one of the animals has developed a visible lesion on either the penis or the sheath, although several of them have characteristic lesions in the testicles and scrotum. The observations on these animals are not yet complete and the full significance of the experiments cannot be ascertained until the course of the infection has been followed much longer. Similar experiments with other mucous membranes are in progress.