YAWS AND SYPHILIS 221 



relationship is like that between variola and varicella, not 

 that between variola and vaccinia. 



Prophylaxis. Infection can be carried from man- to 

 man by direct contact, and the virus is contained in the 

 discharges from the granulomata. The frequency of the 

 early yaw in the neighbourhood of the mouth suggests 

 that food is a frequent source of infection. The com- 

 monest ages for infection, 3 to 5 years, are ages at which 

 children frequently exchange partially eaten pieces of 

 food. Probably flies are also direct carriers of infected 

 material, and the frequency with which ulcers and 

 wounds become infected is probably explicable in this 

 manner. The chigoe (Sarcopsylla penetrans] is by some 

 believed to be an important carrier. There is no evi- 

 dence that the virus can enter through the unbroken 

 skin, but cracks about the mouth, small ulcers as a result 

 of insect-bites, or other sources of irritation are so 

 common in the Tropics that possibilities of infection are 

 numerous. 



There is little risk to well-clad Europeans, even if 

 stopping in the same house as persons with the disease, 

 but amongst European and half-caste children who 

 play about with native children cases of infection are 

 common. It is well to carefully cover up even superficial 

 wounds, and to prevent, if possible, children from having 

 access to natives in a country where yaws is endemic, 

 and to take sufficient precautions to prevent the inter- 

 change of partly eaten articles of food with native 

 children. 



" Guam " disease in most respects corresponds to the 

 description given of the destructive ulcerations about the 

 naso-pharynx so common in Fiji, and there considered to 

 be tertiary frambcesia. Those who consider it a separate 

 disease call it granuloma gangrenosa. It is said to be 

 most common in places where yaws is rare, and to be very 

 rare in some places where yaws is very common. Prob- 

 ably it is the same condition as the Fijian " kanailoma." 



