BACILLUS DIPHTHERIA 575 



The striking distance of diphtheria is not very large, but the organism 

 is relatively resistant to the ordinary influences of exterior corporal 

 circumstances, and may live for considerable lengths of time in mucus 

 or saliva deposited on heating utensils, playthings, pencils, handker- 

 chiefs, etc. In dried bits of membrane the bacilli may live for many 

 weeks as Loeffler has shown. 



Diphtheria is transmitted from one individual to another directly 

 or indirectly by contact or droplet infection as in coughing, etc. It- 

 has been found that individuals may retain virulent diphtheria bacilli 

 in nose and throat for long periods after recovery from the disease. 

 These are the so-called " diphtheria carriers." 



The problem of diphtheria carriers has become one of considerable 

 importance and has been given special prominence of recent years by 

 the studies of Von Scholly, Moss, and Nuttall and Graham Smith. 

 Anderson, Goldberger and Hachtel 37 studied 4,039 healthy people in 

 the city of Detroit, and found that 0.928 per cent harbored bacilli 

 identical morphologically with the Klebs-Loeffler bacillus. This figure 

 is rather lower than those of some other investigators, but would indi- 

 cate, as the writers stated, that there were from 5000 to 6000 diphtheria 

 carriers in the city of Detroit. 



Of 19 cultures isolated from 19 of the carriers, only 2 were virulent, 

 which would indicate that only 0.097 per cent of the people examined 

 carried organisms capable of producing disease. An interesting further 

 point is that the bacillus Hoffmanni was present in at least 41.9 per cent 

 of over 2000 individuals examined, and that 47 cultures, morphologically 

 identified as Bacillus Hoffmanni, were avirulent. This would confirm 

 the impression gained, we believe, by most experienced laboratory 

 workers that a true Hoffmanni can be distinguished with considerable 

 certainty from a Klebs-Loeffler bacillus by morphological examination 

 alone, and that its significance is probably that of a frequently present 

 saprophyte of the throat and pharynx. The studies of Goldberger, 

 Williams and Hachtel also indicate that in examining for diphtheria 

 carriers it is best not to confine oneself either to the nose or throat, but 

 that cultures should be taken from both places in every case. 



Carriers naturally increase in crowded communities in the course of 

 cold weather, when nasopharyngeal catarrhs are common, and, we have 

 seen as high as 17 per cent carriers in a military unit in which diphtheria 



37 Goldberger, Williams and Haclitel, Bull. No. 101, of the Hygienic Labora- 

 tories, of the IT. S. Public Health Service. 



