TREPONEMA PERTENUE 127 



Treponema pertenue, Castellani, 1905. 



Syn. : Spirochceta pertenuis ; S. palliduta, Castellani, 19015. 



Castellani discovered the organism in 1905, in scrapings of yaws 

 pustules. He first described it under the name of Spirochceta pertenuis. 



Treponema pertenue (fig. 58), though delicate and slender, shows 

 great morphological variation both in length and thickness. It 

 may be short, e.g., 7^, but can attain 18/1, to 20 //, in length and may 

 be even larger. In cultures made by Noguchi, thick, medium and 

 thin forms were found, each giving rise to a different type of fram- 

 boesial lesion when inoculated into the testicles of rabbits, thus 

 suggesting the possibility of the occurrence of varieties of T. pertenue. 



The organism is difficult to stain, but occasionally deeper 

 staining granules are found along its body. They may represent 

 a diffuse nucleus. Granule formation 

 similar to that of T. pallidum has been 

 observed by Ranken, using dark-ground 

 illumination. 



Many experiments have been made 

 with a view to establishing the identity 

 of the organism of yaws and also of 

 differentiating between the causative 

 agents of yaws and syphilis. Both 

 monkeys and the human subject have 

 been experimentally inoculated with yaws 

 material and have developed the disease. 



In an early experiment, negroes were 

 inoculated with the secretion from lesions 



. n ji i ,, FlG - $0- Treponema pertenue. 



Of yaWS. All of them developed the (After Castellani and Chalmers.) 



disease, nodules appearing, chiefly at the 



seat of inoculation, in from twelve to twenty days, followed by the 



usual eruption. Similar results were obtained with thirty-two Chinese 



prisoners, who were inoculated with yaws, twenty-eight becoming 



infected. 



A naturally infected yaws patient when inoculated with syphilis, 

 contracted that infection, thus showing that yaws does not confer 

 immunity to syphilis. This has also been observed naturally, when 

 yaws patients have contracted syphilis. 



Experiments with monkeys have been successfully performed. 

 The incubation period varies from sixteen to ninety-two days. 

 Lesions appear first at the seat of inoculation, and in some 

 monkeys the eruption is localized to this spot, though the infection is 

 general, T. pertenue occurring in the spleen, lymphatics, etc. Monkeys 

 inoculated with splenic blood of a yaws patient, and also sometimes 

 with blood from the general circulation, have become infected. 



