Report of the yellow fever expedition to Parà of the Liverpool School of Tropical Medicine and Medical Parasitology / by H.E. Durham.

  • Durham, H. E. (Herbert Edward), 1866-1945.
Date:
1902
Catalogue details

Licence: Public Domain Mark

Credit: Report of the yellow fever expedition to Parà of the Liverpool School of Tropical Medicine and Medical Parasitology / by H.E. Durham. Source: Wellcome Collection.

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    II. PRELIMINARY THOUGHTS ON THE PROBLEM OF THE ETIOLOGY OF YELLOW FEVER Before setting out upon such a mission as that of the investigation of the etiology of yellow fever, it was necessary to frame a sort of programme of the possibilities and the modes to be adopted in dealing with the same. At the outset it appeared that the true infective agent of yellow fever has as yet escaped recognition. Though yellow fever is by no means a virgin field for investi¬ gation, there has been little or no agreement between different observers, in regard to their respective claims. The writings of some authors hardly give evidence that their methods were sufficient or accurate enough to be of value. The study ol yellow fever must be begun again from the commencement, and any organism which may be found will not only have to be constantly found, but it will also have to afford an explanation why it has escaped the attention of other observers. That a yellow fever microbe exists there can be no question. Whether it be protozoal or bacterial in nature, it will be necessary to endeavour to define the mode of transmission and its mode of life in the outer world. The possibilities which may be encountered with either a protozoal or bacterial parasite, suggest a number of themes for consideration. By prejudice there may be an inclination to feel that either kind of parasite may be involved. The epidemiology of the disease (prel. note) is suggestive of the action of an intermediary transmitting agency ; this perhaps might better have been referred to as a transmitting agent rather than as an intermediate host. In the light of our knowledge of other diseases due to animal parasites, it is highly suggestive that this form of parasite would occur ; the apparent limitation of the geography of the disease is likewise suggestive, but though no lasting and endemic hold has been taken in northern climes, the inability to do so has possibly been rather overrated by writers of text-books. On the other hand, the onset and features ol the disease, its rapid course and the subsequent immunity are all more in accordance with our knowledge of bacterial diseases. While granting that we know comparatively little of diseases due to pro¬ tozoal parasites, the hope would rather be for the establishment of a bacillary agent which might offer the opportunity for therapeutic treatment (as by an antitoxin) ; on the other hand, a priori none such would be likely for a protozoal disease in which treatment as yet is based on mere empiricism. In hunting for protozoal parasites, experience with the parasite ol Tsetse disease and of malarial fever should prove useful. It will be necessary to search everything in the fresh state—blood at various stages of the disease, and the organs as soon after death as possible. As with the Tsetse parasite the centrifuge may be useful in separating the protoplasmic structures in the blood from the heavier red blood corpuscles.
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