1370 THE ENTEROIDEA GROUP OF TROPICAL FEVERS 



chronic carriers if precautions are taken to prevent the contamina- 

 tion of the urine during or after micturition. 



In urinary carriers the B. typhosus has its habitat generally in 

 the renal pelvis, which is usually chronically inflamed or cystic, and 

 it has also a secondary habitat in the chronically inflamed bladder; 

 but it appears possible that it may also live in recesses in the pelvis 

 of the kidney, the bladder, the urethra, the prostate, and the 

 vesiculae seminales, from which bacilli pass into the urine. The 

 methods of urine infectivity are the same as faecal infectivity. 



To summarize, the reservoir or carrier of the5. typhosus Eberth is a 

 human host who has suffered from enteric fever, and who affords food 

 and protection for the bacilli in the gall-bladder in the case of intes- 

 tinal carriers, or in some recess or recesses in the urinary tract from 

 the pelvis of the kidney downwards, and in the male in the prostate 

 and vesiculae seminales in the case of urinary carriers. This carrier 

 passes the bacilli into the exterior in the faeces and urine, and these 

 may, in cases of defective hygienic surroundings, directly infect air, 

 food, or drinking-water, or may be conveyed by fomites or by flies 

 to the victim's hands, or food, or food utensils. 



The problem of the carriers of the parat3^phoid bacilli is a similar 

 one. B. paratyphosus B is commonly met with in Europe, where 

 it is disseminated by means of intestinal carriers when it lives 

 in the gall-bladder; but its urinary carriers have so far not been 

 recognized. It has, however, been found in the common house-fly 

 in 191 1 by Nicoll. Its infectivity and its auto-infectivity are well 

 known. B. paratyphosus A is prevalent in India and Ceylon, 

 where precocious and acute carriers are , frequently met with. The 

 germ, however, during the war has now become common also in 

 Europe. It is known that it can live in the gall-bladder for a con- 

 siderable time and pass out in the faeces, and several outbreaks of 

 enteric fever have been traced to this source. 



With regard to the general question of carriers, the persons most 

 liable to be carriers are first of all those who have had attacks of 

 enteric fever, and, secondly, nurses and other attendants upon 

 these patients; while the carrier who is likely to prove most dan- 

 gerous in spreading the infection is a person who is in any way 

 engaged in the preparation or the handhng of food intended for 

 other people to consume, because the infection of the hands is a 

 prolific source of infection for healthy people. 



So far we have merely referred to Musca domestica Linnaeus as 

 an important intermediary host for these bacilli, but the fruit-fly, 

 Drosophila ampelophila Loew, has been definitely implicated by 

 Button in 1909. With regard to the accusations against the bug, 

 Clinocoris lectularius Linnaeus, and the flea, it can only be said that 

 there is as yet no definite proof that they play an active part in the 

 spread of enteric fever. 



To summarize, it may be stated that jB. typhosus, B. paratyphosus 

 A, and 5. paratyphosus B can escape from the bodies of precocious, 

 acute, temporary, chronic, or paradoxical carriers by means of the 



