STREPTOTHRICOSIS. 479 



The geographic distribution is very wide, but no very large series of 

 eases have been studied by any one observer. Collections of such series 

 have been made in America, Germany, France, England, Kussia, Swit- 

 zerland, and in the British colonial possessions. The most frequent 

 incidence is found in certain parts of the Tropics, particularly in India, 

 but, as has been pointed out by Ackland, the disease may be overlooked 

 in a community for a long time until special attention is called to its 

 prevalence. 



According to available statistics the infection is more frequent during 

 young, adult life, but cases have been reported in children and in old 

 people. Males are much more frequently affected than females — 295 

 males to 110 females being given in Leith's statistics, and 65 males to 

 36 females in Ackland's. 



Race, nationality, residence, overcrowding, climate, occupation, and 

 physical condition, to judge from available statistics, seem to exert but 

 a minor influence on the spread of the disease, although a more careful 

 study of a large material may show some of these to have greater signif- 

 icance. 



General environment and mode of living would naturally be expected 

 to have considerable influence as predisposing factors, particularly in 

 determining the part of the body involved. For example, the Madura 

 foot type of infection is most common among people who go barefoot, 

 it being largely a wound infection. 



Strepiothrica are the specific, causative agents of the infection. They 

 have already been considered in Part I of this report, and only a brief 

 summary will here be given. 



Synonyms. — Actinomyces, Nocardia, Obspona, Chenaphe carteri. 



Diagnosis of these organisms is made from morphologic and biologic 

 considerations. They are branching, filamentous organisms, which de- 

 velop slowly into colonies made up of the branches and their "transforma- 

 tion products." These colonies vary in color, size and consistency, and 

 when stained show various changes in different portions. The filaments 

 at the periphery are usually intact, with or without club formation, and 

 the terminals may or may not be radially placed. Toward the center 

 of the colony, or granule, irregular forms, such as coccus- and bacillus- 

 like ones, are found, together with crystals and nonstaining detritus. 



The majority of these organisms may be cultivated on artificial media, 

 where they show various but characteristic biologic properties. That 

 some of them are pathogenic tissue parasites is shown by their action on 

 laboratory animals. 



Morphologically these parasites are rather closely related to some of the 

 branching bacteria. The young filaments vary in width from 0.5 to 1 /x 

 and in length from 5 to 20 // or more. They usually stain homoge- 

 neously, and in some strains taken from lesions they are acid-fast to the 



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