Practical bacteriology, microbiology and serum therapy (medical and veterinary) : a text book for laboratory use / by A. Besson ; translated and adapted from the fifth French edition by H.J. Hutchens.

  • Besson, Albert, 1868-
Date:
1913
Catalogue details

Licence: In copyright

Credit: Practical bacteriology, microbiology and serum therapy (medical and veterinary) : a text book for laboratory use / by A. Besson ; translated and adapted from the fifth French edition by H.J. Hutchens. Source: Wellcome Collection.

    847/928 (page 815)
    precedes epizootics of Mai cle caderas and that among rats which precedes epidemics of plague. Lignieres has mfected rats with Mai de caderas by inoculating them with fleas crushed in salt solution (Nabarro’s translation of Laveran and Mesnil’s 41 Trypanosomes ”). ] Morphology of the parasite.—Trypanosoma equinum was discovered by Elmassian [in Paraguay in 1901]. In fresh preparations it is morphologically indistinguishable from T. brucei and T. evansi ; in stained preparations how- ever the characters of the centrosome differentiate it clearly from allied parasites. The centrosome is very small, and since it stains like the flagellum it is difficult to distinguish. [In trypanosomes of the type T. evansi, on the other hand, the centrosome is very obvious and measures about 0’5/x and stains deep purple (Laveran and Mesnil).] T. equinum measures 22-24y long by about l*5w broad. It multiplies like T. brucei by binary longitudinal fission. Agglomeration in the blood, which is favoured by the addition of normal sheep, pig or horse serum and particularly of serum from bovines, sheep or pigs infected with caderas, gives rise to rosette forms in which the posterior ends are in apposition. The number of trypanosomes in the blood of infected Equidae varies at different periods of the disease. In the early stages the parasites are very scanty but as death approaches they become more numerous ; they are not however constantly present in the blood in the course of the naturally contracted disease, and there are times when no parasites can be found. Trypanosomes are found when the tem- perature of the animal rises above 38° C. but disappear when it reaches 41° C. (Elmassian and Migone). Vitality.—In blood kept at the ordinary temperature Trypanosoma equinum dies rapidly but if the blood be kept in the ice chest the parasite will live for 3 days. The addition of normal serum (fowl, horse, sheep, rat or bovine) to the blood lengthens the life of the parasite by from 5-11 days. [Cultures.—Laveran and Mesnil failed to grow T. equinum on blood-agar at room temperature. Thomas and Breinl using a modification of Novy and M'Neal s medium—chicken-broth-rabbit-blood agar—grew a T. equinum from rabbits’ blood at 22° C. and infected a rat after 29 days’ incubation : sub-cultures failed.] Experimental inoculation.—Horses, mules, asses, monkeys, mice, white rats, guinea-pigs, rabbits and dogs are all susceptible to experimental infec- tion. No symptoms are produced in sheep, cattle and pigs, but the blood of these animals remains infective for mice for about 2 months after inoculation. Birds are immune. Human serum has .a specific action on animals infected with Caderas (Laveran and Mesnil). Laveran was able to cure 10 per cent, of mice experi- mentally infected by inoculating them with human serum. Sheep, goats, bovines and pigs which have recovered from an infection with T. equinum are immune and their serum has for a short time some slight prophylactic property. Specific nature of Mai de Caderas.—Caderas can be differentiated from other Trypanosome infections by a study of the immunity reactions. Dogs which have recovered from an infection with the parasite of dourine and which are therefore immune to that disease are as susceptible to Caderas as normal dogs (Lignieres). A goat and a sheep cured of and immune to Nagana were just- as susceptible to Caderas as normal control animals. The serum of animals cured of Nagana has no action on T. equinum (Laveran and Mesnil).