The authorities generally discuss extensively the points of distinction between yaws and syphilis. This is probably more connected with possible relationship than practical importance in diagnosis.
Laboratory Diagnosis.—The staining of the juice from yaws tubercles by the India ink method or with Giemsa’s stain is the usual procedure.
Baermann gives the percentage of positive Wassermann reactions in untreated, clinically positive cases, as 80 to 100%; in treated cases, 50%, and in the latent ones as from 35 to 40%. In an examination of the serum of 281 cases of gangosa, Halton obtained 37.3% positive Wassermann reactions. Kerr found that 73.8% of 2,429 natives of Guam had had yaws, usually in childhood.
Among other diseases which may be confused with yaws, particularly as regards the nasopharyngeal ulcerations of tertiary yaws, may be mentioned American cutaneous leishmaniasis. The differentiation rests in finding Leishmania tropica in such lesions.
Sections from a yaws tubercle treated and sectioned according to Levaditi’s method show the treponemata in the region of the thickened interpapillary pegs of the epidermis.
Prognosis
This is almost entirely favorable as regards danger to life. The death rate is approximately ½ of 1% and such fatalities generally occur in young children in whom secondary infections develop on the site of the ulcerating yaws lesions.
Prophylaxis and Treatment
Prophylaxis.—Daniels thinks the frequency of infection about the angles of the mouth, which frequently show fissures, is explained by the exchange of particles of food or other substances by children, thus transferring the infection.
Of course care should be taken to prevent articles of clothing contaminated with yaws discharges from acting as infecting agents.