Trypanosoma brucei

Trypanosoma brucei is one of Protiste parasite about the Trypanosomatida. The species cause diseases, Trypanosomiase S at the man and the animals in Africa. The species is transmitted by bites of Tsetse fly.

Trypanosoma brucei gambiense and has slower onset with has long incubation period. The acute form is caused by the sub-species Trypanosoma brucei rhodesiense .

Animal African trypanosomiasis, but Nagana, edge Be caused by the sub-species Trypanosoma brucei brucei although several other species off trypanosomes edge also causes this disease. -->

Trypanosoma gambiense

The trypanosome responsible for the Maladie of the sleep is Trypanosoma gambiense . It one of is more studied. Its life cycle requires two hosts to develop and reproduce. In addition to the man, it needs the Tsetse fly ( Glossina palpalis ) which is its vector.

The trypanosome lives in the Sang, the osseous Moelle and the céphalo-rachidian Liquide or LCR of the man. One also finds it at the Antilope S and the Bovidé S. Its size is of 20 µ or micrometers length on 2 to 3 µ or micrometers broad, they are entirely mobile.

When the Tsetse fly spade an infested person, the trypanosomes pass in the intestine of the fly and they will multiply there. Then they will pass in the Proventricule then will go up in the salivary Glandes or the multiplication continues (asexual).

The parasites will pass 18 to 25 days in the fly then will be transmitted to the man by Piqûre. The Period of invasion of the parasite is done after incubation from 10 to 15 days. The propagation is also done in the Lymphe what causes the Fièvre S. There is hypertrophy of the Foie (Hépatomégalie) and of the Rate (Splénomégalie).

A few weeks afterwards, they invade the Méninge S and the céphalo-rachidian Liquide causing first of all Céphalée S then Troubles engines and Troubles psychological reflexes then Disorder . the disease is mortal in a few months.

geographical Distribution and importance of the disease of the sleep

Affection almost always fatal if it is abandoned with itself, curing only at the price of heavy after-effects if it is not treated as of the 1st stages and answering only the therapeutic dangereous ones because of their weak safety margin, the disease of the sleep was, for a long time, the large plague of intertropical Africa: Western, central and Eastern Africa.
the fights carried out since 1/2 century, with systematic tracking and treatment of the patients, measurements against the glossines intermediate hosts and vectors, protection chimioprophylactic of the healthy subjects, fortunately modified the situation. However, the persistence of many residual hearths and the difficulties encountered in the application of the drastic measures at the stage where required to them is not obvious any more for all, continue to maintain, in these vast African territories, the threat of the disease.

Morphology

The 2 trypanosomes met at the man in the only form Trypomastigote, are morphologiquement indifférenciables one of the other. They are recognized at their round posterior end and with their kinétoplaste subterminal, constant characters through the great polymorphism of whipped group “brucei” which makes meet, beside the normal forms, of the short forms practically without whips free, of the forms very lengthened with of 40 µ whips and the shapes with vegetative core rejected backwards.

Biology

Very mobile the 2 trypomastigotes live initially in the Sang, the Lymphe and the ganglionic Suc, multiplying actively by simple longitudinal division; more or less early, they invade LCR and multiply there. The evolutionary cycle requires an intermediate host and vector, a piqueuse fly of the kind Glossine (dipterous brachycère) called locally Tsé-tsé. The forms present in blood, pumped with its meal by the glossine multiply initially in its intestine then go up towards the proventricule and the salivary Glandes where after the passage by the stage épimastigote, they on standby will accumulate in infectious form Trypomastigote metacyclic (squat form with whips free almost non-existent). The cycle is buckled when the infected glossine, pricking a new subject, injects to him, with saliva, 3 to 400 Trypanosomes metacyclic Infectieux. Trypanosoma gambiense, person in charge of the relatively benign trypanosomoses of the African West, is transmitted by the glossines group Glossina hygrophile palpalis, flies living especially in the primary forest, along the coast and the forests galleries of the great rivers; it is the trypanosome of which the " dème" completely adapted to the man. Trypanosoma rhodesiense, agent of the serious trypanosomes of the center and the African east, is transmitted by xerophilous glossines group alive Glossina morsitans in the zones of high savannas; incompletely adapted to the man, it has an important reserve of animal virus.

Clinical

The metacyclic trypanosomes inoculated by the puncture of the glossine multiply initially on the spot, around the point of inoculation (Trypanome), then diffuses while multiplying, by lymphatico-blood way to finally reach LCR and SNC. This pathogenic cycle is the directing wire which makes it possible to maintain the unicity clinical of the disease through tables which, in fact, vary only by the reciprocal duration of the various demonstrations.

To the traditional tables of forms of the West, to torpid evolution and less dark forecast and forms of the East, to the signs of very early nervous attacks and to the fatal evolution in 3 or 4 months, are added today, thanks to the electroencephalogram S, the concept that the nervous attack, whatever the trypanosome causes, is very often extrèmement early, preceding by much its clinical translation. It is there a capital concept which shows that, only, a very early diagnosis and appronfondi will make it possible to found the treatment the stage of real effectiveness: before the nervous attack.

the inoculation is revealed only seldom by the pain of the puncture of the glossine infected.

incubation , dumb woman, lasts 10 to 20 days.

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