848 microbiology of diseases of man and domestic animals 



Yaws or Frambocesia 



Treponema pertenue — Castellani, 1905 



This is a disease of the tropics which was formerly confused with 

 syphilis. It is characterized by the presence, on any part of the body, 

 of more or less numerous warty fungoid lesions which tend to ulcerate. 

 In this disease a primary lesion appears after a period of incubation and 

 this is followed after another interval by a general eruption. It is not 



Fig. 183. — Treponema pallidum (in centre) and the Spirocheta refringens. 

 {Greene's Med. Diagnosis) 



a venereal disease as is the case with syphilis. It is caused by a 

 slender spirochaete, Treponema pertenue, which is morphologically 

 identical with the organism of syphilis. Animals which have been 

 immunized to one of these diseases are found to be still susceptible to the 

 other. The organisms in yaws are present in enormous numbers in the 

 hypertrophied and swollen epidermis of the lesions whereas in syphilis 

 they are confined to the deeper tissues. The disease responds more 

 favorably even than syphilis to treatment with salvarsan which may 



