57C) PATHOGENIC MICROORGANISMS 



and other respiratory diseases were prevalent soon after they had to be 

 crowded together during Transatlantic transportation. The carrier 

 state in kitchen personnel is particularly important, and attention 

 should be paid to these groups in a community whenever the source of 

 infection is being traced. Indirect and direct contact with carriers 

 is probably the most common method by which the disease is kept 

 going in modern communities. Less important, though still of some 

 significance, is food transmission and milk epidemics have not been 

 uncommon. Also, these will mean infection of the milk by a milk 

 handler, who is a carrier or suffering from a mild diphtheria. How- 

 ever, in one instance diphtheria bacilli were isolated from the inflamed 

 udders of a cow. 



The carrier problem thus becomes the most important epidemic- 

 logical feature. The carriers may either be temporary or chronic. 

 Convalescent diphtheria cases usually get rid of their bacilli sponta- 

 neously within two, three, or four weeks. Healthy individuals exposed 

 to cases or carriers as a rule do not keep their organisms more than 

 either a few days or a few weeks, depending perhaps to some extent 

 upon the condition of the mucous membranes. A small percentage 

 remain chronic carriers and, in isolated instances, it has seemed almost 

 impossible to free these individuals of their diphtheria bacilli. They 

 are, however, such definite menaces that prolonged isolation and vigor- 

 ous attempts at cure must be made for the protection of the com- 

 munity. In all such cases, virulence tests should be made, since pro- 

 longed isolation implies so much interference with the life of the affected 

 individual that it would be quite improper to confine a person unless 

 we were sure that the organisms carried by him were capable of trans- 

 mitting the disease. 



Many different methods have been employed for the freeing of 

 carriers. Not a single one of them, however, has been permanently 

 successful. Practically all the ordinary throat antiseptics, peroxide 

 of hydrogen, permanganate of potassium, iodin and glycerin, weak 

 formaldehyd, various hypochlorite solutions have been used, some of 

 them with occasional success, but without regularity in any of them. 

 Acriflavine and other dyes have been applied and implantation of 

 staphylococci or some of the acidophilic bacteria upon the throat in the 

 hope of driving out the diphtheria bacilli by bacterial competition have 

 been tried and have usually failed. The spraying of the throat with 

 pyocyanase was in vogue a few years ago, but cannot be said to have 

 brought encouraging results. It is probable that quite the most impor- 



