252 The Philippine Journal of Science iszs 



the Mount Fletcher District in South Africa; Mount Fletcher 

 is 5,500 feet (1,800 meters) high. 



In Manila, for many years, physicians have frequently spoken 

 of the occurrence of yaws in the Mountain Province of northern 

 Luzon at elevations varying from 2,500 to more than 5,000 feet 

 (800 to 1,700 meters). I recently passed through this prov- 

 ince on a brief visit. In exceptional instances, I found that 

 yaws occurring in the people there might readily have been 

 contracted during visits to the adjacent lowlands where the 

 infection is prevalent. This explanation, however, does not 

 apply in the majority of cases. Doctor Pick, of the Philippine 

 Health Service, estimates that he has treated 2,800 cases of 

 yaws in the Mountain Province. He describes the lesions as 

 limited largely to the mouth, the anus, and the vulva, with 

 but few granulomata occurring on other portions of the body. 



The limitation of yaws to the Tropics inevitably suggests 

 that it may possibly be transmitted by bloodsucking insects in 

 analogy with other spirochetal diseases such as relapsing fever. 

 This idea has been emphasized by Bahr. In its support it 

 should be mentioned that the mother yaw frequently develops 

 on the lower extremities, which recalls that, in bubonic plague, 

 the causative organism is commonly introduced in the lower 

 extremities, the initial buboes appearing in the groin. 



Although the circumstantial evidence, suggesting an inter- 

 mediate insect host, should not be forgotten, it seems advisable 

 to adhere to the prevailing view that yaws is ordinarily dis- 

 seminated by contact. The only feasible procedure for attempt- 

 ing the control of yaws in a given community consists in 

 eradicating the foci of infection by treatment of the individual 

 patient. 



No plausible suggestion has been advanced concerning the 

 probable explanation of the usual restriction of yaws to the 

 warmer regions of the Tropics. In seeking for a solution, it 

 is perhaps well to keep in mind the possible effect of surface 

 temperature upon the development of the granulomata. Con- 

 sidering first the typical case of the lowlands, it is noteworthy 

 that, of the multiple miliary lesions distributed metastatically 

 from the mother yaw, only a small proportion progress 

 to fully developed granulomata. Although these granulomata 

 may develop on any part of the body, they show a striking 

 predilection for the muco-eutaneous orifices, for the axillae, and 

 also for the groin and the popliteal spaces. These locations 



