22.3 Sellards: Public-health Aspects of Yaws 253 



are either moist or they are protected, to some extent, by the 

 body clothing. However, in the Mountain Province of the 

 Philippine Islands it would seem that the majority of the 

 patients escape the usual general distribution of yaws over 

 the body. These people are very primitive. The men wear 

 only a breechcloth, and the clothing of the women is inadequate 

 to maintain the ordinary surface temperature of the body. 

 The possibility naturally suggests itself that, in the dry skin 

 exposed to the low temperature, the granulomata of yaws 

 might develop only with difficulty. 



INCIDENCE 



In drawing up any detailed plans for the treatment of yaws 

 in an endemic area, one is often embarrassed by the imprac- 

 ticability of securing even an approximate estimate of the total 

 number of cases. On making inquiries, one is frequently told 

 that almost everybody has fresh active yaws. To assume that 

 such is the case would be a fallacy. There is considerable clin- 

 ical and also some experimental evidence that the majority of 

 patients do not pass through more than one period of typical 

 florid granulomatous eruption. Let us allow the fairly liberal 

 period of two years for the granulomatous stage and assume an 

 average duration of life of fifty years for the community. 

 Considering the disease to be endemic rather than epidemic, 

 the maximum number of cases in the granulomatous stage 

 would average 40 per 1,000 of the population. Obviously such 

 a calculation is merely of theoretical interest. In Paraiiaque, 

 yaws has been endemic for many generations; recently the 

 Philippine Health Service treated nearly all of the active cases. 

 There were 275 cases in a population of 8,541, or 33 per 1,000 

 of the population. Unfortunately, in many isolated districts of 

 the Tropics even an approximate census of the population is not 

 available. 



The disease is restricted almost entirely to the native people 

 and especially to those of the poorer classes who are inclined 

 to give scant attention to simple personal hygiene. In many 

 localities, yaws might well be classed as one of the diseases 

 of childhood. At the Paraiiaque clinic 69 per cent of the cases 

 occurred in children under 11 years of age, and the total of 

 those under 16 years was 88 per cent. At Yamasa in the 

 Dominican Republic the parents freely make a practice of ex- 

 posing children to the disease because they feel that the sequelae, 



