Preliminary report on the tsetse fly disease or nagana, in Zululand / By Surgeon-Major David Bruce.
- Bruce, David, Sir, 1855-1931?UNAUTHORIZED.
- Date:
- 1895
Licence: Public Domain Mark
Credit: Preliminary report on the tsetse fly disease or nagana, in Zululand / By Surgeon-Major David Bruce. Source: Wellcome Collection.
Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.
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![These five experiments show abundantly that horses cannot be taken with impunity for a few hours into the Flij Countrg, even although they are not allowed to eat or drink there, and they afford a strong presumptive proof that the disease is carried to them by the Tsetse Fly. This last series of experiments, however, proves less than at first sight it might be. supposed. It only proves that susceptible animals cannot be taken into the Fly Country, even although they are not allowed to eat or drink there. It does not absolutely prove that the disease is carried to them by the Tsetse Fly. There may be other ways of taking the disease, for example by inhalation. The disease called Ague or Malarial Fe ver in man is of all diseases probably the one most nearly related to the Fly Disease in animals. They are both caused by blood parasites belonging to the Protozoa, and they are both found under similar physical conditions. In the case of the much studied and familiar Malarial Fever none have up to the present had the courage to assert that man would be immune by merely taking care what to eat or drink while in a malarious district, or in other words only to eat cooked food and drink boiled water while there. On the contrary it is asserted by the latest authorities that merely breathing the air of malarious districts is sufficient to set up the disease ; in other words, that the parasite can obtain entrance to the system from the air. This, is a hard thing to understand, and in order to make it possible the parasite of the Fly Disease must be able to exist in some other form than that in which it is found in the blood. The supposition would be that it forms a resting stage or spore form in which it can exist as a dry impalpable dust. For my part I have much difficulty in believing that animals are infected as a rule with Fly Disease by inhaling the materies morbi, and until I find animals still susceptible to the disease which are protected in some way or other both from feeding and the fly, I shall continue to be sceptical. On account then of the lack of absolute proof furnished by the last experiments, ] set myself on the 22nd November to try to infect susceptible animals with the disease by having them bitten by flies brought up daily from the low country and straightway placed on the animals. (</.) Is the Tsetse Fly capable of giving rise to the disease if taken out of the Fly Country into a healthy locality? The method of carrying out this experiment was to go down to the Fly Country in the early morning, catch the flies, return to the top of the Ubombo and straightway place them on the animal under experiment. The greatest care was taken that the flies were caught on a perfectly healthy animal, as to have allowed them to puncture one already affected by the disease wjuld naturally vitiate the experiment. The time which elapsed between catching the flies and placing them on the animal under experiment varied from four to seven hours. The following experiments give the dates, the number of flies used, and the result:— Exp. 225. Horse.—In good condition. November 22nd.—Brought up ten Tsetse Flies from the low country and placed them on this horse. November 28th.—Ten fresh flies. ,, 30th.—Nine fresh rlies. December 1st.—Five fresh flies. 2nd.—Thirteen fresh flies. „ 4th.—Twenty fresh flies. ,, 6th.—Seven fresh flies. „ 8th.—Thirty fresh flies. 11th.—Eleven fresh flies. 14th.— Fourteen fresh flies. 15th.—To-day this horse is seen to be out of sorts, his temperature has risen and hi* blood contains the haDmatozoa of Fly Disease.](https://iiif.wellcomecollection.org/image/b21364655_0081.jp2/full/800%2C/0/default.jpg)
