Further report on the tsetse fly disease or Nagana, in Zululand / by Surgeon-Major David Bruce.

Bruce, David, Sir, 1855-1931.

Date:: 1896

Credit: Further report on the tsetse fly disease or Nagana, in Zululand / by Surgeon-Major David Bruce. Source: Wellcome Collection.

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$6? To return to Xagana, what do we know of the disease? We know that, it i* caused by the entrance into the blood of a minute parasite which multiplies there and causes death, that this parasite exists in the blood of many animals and that it is conveyed from animal to animal bv the Tsetse Flv, or bv the eating of the raw flesh of animals atlected by the disease. A\ e also know that the disease is limited to certain tracts of country having certain physical features, but that its distribution in these tracts is very variable. T\ e do not know how the parasite causes death, but surmise that it may do so by the poisonous action of some substance or substances elaborated or secreted by it, or by producing a progressive haemolysis and anaemia, leading to a form of auto-intoxication. We do not know all the animals in which this parasite may exist, but bulging from the number of domestic animals in which it is fatal, we may consider that it has a wide range. It may exist not only in the koodoo, wildebeeste and other big game, but it also may exist in the wild cats, rats, birds, and eyen fish of the Fly Country. We do not know whether there are other species of fly which conyey the disease besides the Tsetse, but this perhaps is a minor consideration. We do not know of any method at present of isolating the hypothetical poisonous substance elaborated by the hmmatozoon so as to be able to study it or to render animals immune to it by gradually increasing doses. No experiments liaye, as far as I am aware, been made in this country in the direction of studying the effect of the serum of animals in whose blood the hsematozoa have been numerous. Dr. Lingard has, however, made a few with a negative result in Surra. As treatment of disease by means of serum is very popular at present and I may be blamed for not having entered more into this aspect of the subject, 1 give Dr. Lingard'e results in ecctenso. “ THE SUBCUTANEOUS INOCULATION OF BLOOD AND ITS DERIVATIVES IN ITS DIFFERENT “ FORMS, OBTAINED FROM ANIMALS SUFFERING FROM, OR WHICH HAD LATELY “ SUCCUMBED TO, SURRA. “ A series of experiments were conducted in order to test the efficacy or otherwise of the blood serum “ as a protective agent against inoculated ‘Surra,5 or in other words to ascertain whether any substance capable “ of conferring immunity against the disease was present in it when obtained from animals in whose circulation “ the haematozoon of Surra had been swarming for some days previously. In the first series fresh blood “ containing numerous haematozoa was drawn from the horse immediately after death into sterilised glass “ vessels, and set aside for several hours in order to allow of the •serum separating. The serum was then “ transferred to one of M. Pasteur’s filters, and forced through a porcelain cylinder. Three rabbits and two “ guinea pigs were then subcutaneously injected with varying quantities during a period of three days. On the “ evening of the third day each animal received subcutaneously 0 2 e.c. of blood containing numerous hsematozoa “ another animal in each ease receiving a like quantity so as to act as control experiments. “ Rabbit A, which received 3'0 c.c. serum after inoculation with the soiled Surra blood, survived the a fizst appearance of the haematozoon twenty-four days. “ B received G’O c.c. serum ; survived twenty-two days. “ C received 9‘0 c.c. serum ; survived forty days. u The control animal survived forty-seven days. “ In the case of the guinea, pigs— “ X received 6'0 c.c. serum, and survived the first appearance of the haematozoon after inoculation with 11 the soiled Surra blood thirtv-four davs. “ Y received 6'0 c.c. serum, and survived sixty-six days. The control animal survived the first appearance of the haematozoon in the blood eighty-four days.55 “ TABLE XIX. Animals. Date of Sub¬ cutaneous Injections. Quantity of Horse Serum Injected. Date of Inoculation with Blood . . containing the Heematozoa. Quantity of Blood Inoculated. Date of the first Appearance of the Hse rsatozoa in Blood. Date of Death. Number of Days elapsing between Inoculation and Death. Rabbit A .. e.c. 3 0 c.c. 02 D. M. T. 18.12 90 D. M. T. 30.1.91 • - P •« D • • • • • « GO —• 0-2 18.1290 8.1.9] „ c. — 9 0 — 0*2 18.12.90 2G.1 91 | . __ Control .. .. — — 0 2 — — Guinea-pis X — _ — 0 2 20.12.90 22.1.91 ,i T .. _ _ — 0 2 20.12.90 23.2.91 — ,, Control _ . 0-2 —$