Reports and notes of the Public Health Laboratories, Cairo. No. 1, 1917.

Date:
1918
Catalogue details

Licence: In copyright

Credit: Reports and notes of the Public Health Laboratories, Cairo. No. 1, 1917. Source: Wellcome Collection.

    29/144 page 17
    et Yo The proportion of the positive cultures given by the derived figures in the various periods of the disease can of course be regarded as approximate only within a large range of error, on account of the small numbers involved, but they may give some indication of the probability of obtaining a positive blood-culture in a case of enterica. The figures probably still err in the direction of being too small, since the proportion 1 : 4 which was made the basis of the calculation is itself derived from suspected and not from actual cases of enterica ; had all the cases actually been enterica, the proportion of negative cultures would have been lower and the factor x 3 correspondingly higher. ; Feces. There /is no point in determining the proportion of cases in which the feeces were examined and found positive, since, as already remarked, the totality of the cases contain an unknown and unattainable proportion not really enterica. It will, however, be of interest to elucidate three points from the data provided by the investigation, wiz. :— (1) The proportion of positive cases in which the feces were examined and in which the feeces were. found positive. . (2) The proportion of positive specimens of feeces found in positive cases of enterica. (3) The proportion of positive specimens of faeces in cases in which at least one specimen of faeces proved positive. (1) To determine the proportion of positive cases in which the feeces proved positive it is necessary to limit the analysis to cases in which the feeces were examined and which were proved positive on other grounds than by the examination of the feces, that is, by blood-culture or from the urine. Obviously, cases proved positive only by the examination of the faeces must be omitted. The result of this analysis is shown in Table IV, and since the number of specimens examined might be expected to influence considerably the probability of obtaining a positive specimen, the cases have been arranged in the table according to the number of specimens examined, the insertion of a case in the positive column indicating that at least one of the specimens proved positive. TABLE IV. ‘ ; Numl ete: pea iniod Total Positi Positive Number of Specimens re) eces eXalmined, otal. ositive. per Cent. Z We specimer: chee wks coe. 63 S 13 Dyno Specumnens.)25° Gra. abel wae! cae 32 7 22 Three or more specimens ne Soe 23 he 9 30 Dotabrn goss. 118 22 19 Since the specimens of faeces were examined after the blood-cultures and usually simultaneously with the specimens of urine, there is probably very little tendency to the distortion of these figures by the factor which was seen to have disturbed the analysis of the blood-cultures. ~ (2) To determine the proportion of positive specimens of faces found in established cases of enterica it is also necessary to confine the analysis to cases proved positive by blood-culture or from the urine. The results of the analysis of the specimens from these cases is set forth in °
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