714 PATHOGENIC MICROORGANISMS 



ticularly found in connection with cases of so-called infantile diarrhea, 

 and it is not impossible that many cases of diarrhea in children may be 

 due to this organism. 



In many countries there seem to be endemic foci of dysentery. This 

 has been particularly studied in France where outbreaks of dysentery 

 seem often to have started in the central part in the neighborhood of 

 Tours, and it is not unlikely that in our own country there may be scat- 

 tered dysentery foci in the large cities of the north and in some parts of 

 the south. 



Dysentery may be conveyed by a number of different agencies. It 

 is easy to understand that in a disease in which the movements become 

 fluid and very frequent, and in which many mild unhospitalized cases 

 may exist, the scattering of infectious material is very much more 

 important epidemiologically than it would be in a disease like typhoid 

 fever. In consequence, transmission from man to man by hands and 

 indirect contamination of food, etc., is common during epidemics. The 

 organisms may remain alive for a considerable period in the soil, as we 

 have seen, and under camp conditions, infected latrines may contam- 

 inate water supplies and by the intervention of flies, scatter the organ- 

 isms to the food. Fly transmission is of the utmost importance in 

 dysentery among armies in the hot weather. It was probably the most 

 important means of transmission during the American Army epidemic 

 spoken of above. Large water epidemics, as described in the case of 

 typhoid fever, are uncommon, although isolated ones have been 

 described. 



Dysentery carriers unquestionably exist. The organisms may 

 persist for months in the intestinal canals of convalescents and have 

 been described in the stools of individuals who give no history of having 

 had the disease. The carrier problem in dysentery is a very difficult 

 one because the isolation of small numbers of dysentery bacilli from 

 stools is even more difficult than in the case of typhoid bacilli. It has 

 been suggested that chronic carriers may harbor the organisms in the 

 gall bladder, but this is not definite. 



Shiga who has made extensive epidemiological studies on dysen- 

 tery, expresses the opinion that the chief element in the spread of 

 dysentery is the carrier. The first positive carrier examination 

 was made by Conradi 39 who isolated dj^sentery bacilli from the 

 stools of three perfectly healthy children during the occurrence of a con- 



39 Conradi, Festschr. fur Robt. Koch, Jena, 1903, cited from Lentz, Kolle and 

 Wassermann, 2d ed., vol. 3. 



