Report on the public health / Southern Rhodesia.

  • Southern Rhodesia. Department of Health.
Date:
[1924]
Catalogue details

Licence: Public Domain Mark

Credit: Report on the public health / Southern Rhodesia. Source: Wellcome Collection.

    37/70 (page 29)
    for para-typhoid. Some blood cultures were also made. Other organisms causing similar disease are kept in stock, and are tested against when necessary. Blood and stool cultures are not asked for as frequently as is advis¬ able, as they often give a result in the first week of the diseases (while the agglutination test is still negative), and thus give earlier and con¬ sequently more valuable information. F. Fevers of Doubtful Causation.—It will be seen that, out of a large number of cases examined for malaria, Malta and enteric fevers, only a few gave positive results. Most of the negative cases were probably malarial, as a negative for enteric or Malta fever can usually be accepted as such, while a negative for malaria is not so reliable; but there remain a certain number of cases in which the diagnosis is doubtful, and these are of the following types :— (1) Cases giving a negative agglutination test for typhoid, para¬ typhoid and Malta fevers. This generally means of course that the patient has not got these diseases, but some other infection which has next to be ascertained; but in a few cases of typhoid and Malta the agglutination test is negative, either because the infection is so slight that no re-action (giving agglutination) takes place, or the infection is so severe that the patient is overwhelmed and no re-action can be pro¬ duced. In such cases we have to repeat the test or do cultures, but this means delay in diagnosis. It is clear that, by means of research, we should aim at some test or improvements that will give an earlier and correct diagnosis, and this point is being worked upon. (2) Cases which are doubtfully (because weakly) positive to the test, and yet are not suffering from the disease at all. Normal people, cases of pyrexia, previous inoculation, previous disease or similar disease may all give a positive test, and so cause doubt in diagnosis. Further tests usually clear the matter up, but this again means delay. Research is again necessary for improvement of diagnostic methods, and it is hoped that our new test, described in the next paragraph, will prove of value in this direction. (3) Cases which give a positive agglutination, say, for both typhoid and para-typhoid, or both typhoid and Malta fevers. As double infec¬ tions are rare, these cases are usually ones of single infection which happen to agglutinate the other organism because it is similar, or some of the causes mentioned in the second paragraph may be at work. It is often difficult to say which is the infecting organism, and it may require several tests to decide this, which all means delay. Under research, therefore, we devised last year a new test, called the saturation test, which gives promising results and will be further tested and reported on this year. It is briefly as follows :—If an organism be saturated with a heated allied (but not its own) agglutinating serum, it will be found that it can now no longer be agglutinated by the allied serum, but can still be agglutinated by its own serum. Thus a case of, say, typhoid will by this test give a positive for typhoid only, and cannot give a positive for any other disease. I have gone rather fully into the above points to make it clear how important the question of early and accurate diagnosis is in such common and important diseases as are mentioned above. There is a tendency to regard research as only called for in a few, perhaps rare or striking diseases, but it is obvious that it is equally important in such common