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Haemoflagellates

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الكلية كلية التمريض     القسم قسم العلوم الطبية الاساسية     المرحلة 2
أستاذ المادة ميس هادي جبر       20/02/2019 09:11:33
1. L6: B:Class Haemoflagellates: Leishmania & Trypanosoma
Leishmania tropica
Amastigotes
The average roundish to oval amastigote measures 5 by 3 ?m in size. The amastigote consists of a nucleus and a kinetoplast. The large single nucleus is typically located off – center, sometimes present more toward the edge of the organism. The dot like belpheroplast gives rise to and is attached to a small axoneme. The axoneme extends to the edge of the organism. The single parabasal body is located adjacent to the belpheroplast.





Table ( ) : Leishmania tropica Amastigote : Typical characteristics
Size 3 by 5 ?m
Shape Round to oval
Nucleus One , usually off center
Other features Kinetoplast present , consisting of :
Dotlike belpharoplast from which emerges a small axoneme
Parabasal body located adjacent to the belpharoplast .

Promastigotes
The typical Promastigote measures 9 to 15 ?m in length. The large single nucleus is located in or near the center of the long and slender body. The kinetoplast is located in the anterior end of the organism. A single free flagellum extends anteriorly from the axoneme.





Table ( ) : Leishmania tropica Promastigote : Typical characteristics
Size 5 to 15 ?m long
Appearance Long and slender
Nucleus One , located in or near center
Other features Kinetoplast located in anterior end
Single free flagellum , extending from anterior end


Life cycle

Sandflies of the genera Phlebotomus are responsible for transmitting Leishmania tropica promastigotes into unsuspecting humans via blood meal, resulting in a skin bite. The promastigotes quickly invade the reticuloendothelial cells and transform into amastigotes, which actively reproduce, causing tissue destruction reproduction and invasion of additional cells then occurs . The skinand mucous membrane areas of the body are primarily affected. The amastigote serves as the infective stage for the sandfly. Upon ingestion, during a blood meal of an infected human, the amastigotes transform back into promastigotes in the fly midgut. These promastigotes multiply, and the resulting developed forms eventually migrate into the salivary gland of the fly, where they are ready to be transferred to a new human during a blood meal. Thus the cycle repeats itself.







Clinical symptoms

Cutaneous Leishmaniasis. Also known as Old World leishmaniasis, Oriental sore, and Baghdad or Delhi boil, cutaneous leishmaniasis is characterized by one or more ulcers containing pus that generally self – heal. Infected patients initially develop a small red papule , located at the bite site , that a typcally 2cm or more in diameter and may cause intense itching . the incubation time and the appearance of the papule vary with each subspecies . diffuse cutaneous leishmaniasis ( DCL ) occurs especially on the limbs and face when immune response fails to take place .


Laboratory diagnosis

Laboratory diagnosis of L. tropica consists of microscopic examination Giemsa – stained slides of aspiration of fluid underneath the ulcer bed for the typical amastigotes. Culture of the ulcer tissue may also reveal the promastigote forms.


•Trypanosoma: The cell of this genus is tall with one central nucleus and the motile generator located in the terminal of parasite.
1. The flagellate belong to these two genus pass through the life cycle; the live cycle between two host: vertebrate host (terminal host like human)and arthropod host (mediated host like the fly) in many stages with different shapes, through the shape of the body, presence of flagellate or absent, the shape locate of motile generator and the presence of waved membrane or absent ,as following:
A. Amastigote: the parasite circular or ovum in shape,the nucleus lies near the center and it in front of it present motile generator which extend short flagella from it and have not waved membrane.

B. Promastigote: the body is spindle with nucleus in the center and motile generator located near the beginning of the body arise a flagellate from generator extend out of the body and have not waved membrane.


C. Epimastigote: the body is tall and motile generator lies in front of the nucleus that move little away from the center of the body and arise on it flagellate that connect with the body and with the waved membrane therefore extend with free end.



D. Trypomastigote:The body is spindle and the nucleus lies in the center,the motile generator lies in the last part of the parasite and arise from it a flagellate extend along the external adage to the waved membrane and the end of flagella is free.

Note:the parasite that belong to Leishmania pass through the life cycle in amastigote
and promastigote forms while Trypanosoma pass through the life cycle with all forms.

• Leishmania:
A. L.donovani: causes visceral Leishmianiasis, Kalaazar and Dum Dum fever. Spleenomegaly & hepatomegaly. Parasite in human present in amastigote form, while in the insect (Sand fly) promastigote.
B. L.tropica : causes tropic sore or Baghdad boil, oriental sore and cutenaeous
Leishmianiasis, the insect transport L.tropica is sand fly.
C. L. braziliensis : causes Mucocutaneous leishmaniasis.

•Trypanosoma:
T.gambiense: causing sleeping disease to human and the mediated host is Tse_Tse fly.
T.cruzi: cause chagas disease, American trypanosomiasis.
H
Diagnosis of L.donovani
1. thick blood film (amastigot). 2. skin test: is used to measure delyed hypersensitivity.
3. detection of antibody by ELISA. 4. can be cultured on NNN media (Novy Macneel Nicolle).


المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
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