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    Trypanosoma

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    A 7 M D M 7 M D
    1. The document discusses various Trypanosoma species that cause diseases in humans. 2. It describes the transmission, geographical distribution, pathogenesis and clinical features of African trypanosomiasis and Chagas disease. 3. Key points covered include the life cycles of the parasites, modes of transmission by tsetse flies and triatomine bugs, symptoms of the acute and chronic stages of disease, and methods of diagnosis.

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    Trypanosoma

    Uploaded by

    A 7 M D M 7 M D
    168 views21 pages
    1. The document discusses various Trypanosoma species that cause diseases in humans. 2. It describes the transmission, geographical distribution, pathogenesis and clinical features of African trypanosomiasis and Chagas disease. 3. Key points covered include the life cycles of the parasites, modes of transmission by tsetse flies and triatomine bugs, symptoms of the acute and chronic stages of disease, and methods of diagnosis.

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    1. The document discusses various Trypanosoma species that cause diseases in humans. 2. It describes the transmission, geographical distribution, pathogenesis and clinical features of African trypanosomiasis and Chagas disease. 3. Key points covered include the life cycles of the parasites, modes of transmission by tsetse flies and triatomine bugs, symptoms of the acute and chronic stages of disease, and methods of diagnosis.

    Copyright:

    © All Rights Reserved
    168 views21 pages

    Trypanosoma

    Uploaded by

    A 7 M D M 7 M D
    1. The document discusses various Trypanosoma species that cause diseases in humans. 2. It describes the transmission, geographical distribution, pathogenesis and clinical features of African trypanosomiasis and Chagas disease. 3. Key points covered include the life cycles of the parasites, modes of transmission by tsetse flies and triatomine bugs, symptoms of the acute and chronic stages of disease, and methods of diagnosis.

    Copyright:

    © All Rights Reserved
    of 21

    Trypanosoma

    Causes
    Trypanosomiasis

    West African East African American


    Trypanosomiasis Trypanosomiasis Trypanosomiasis
    T.brucei gambiense T.brucei rhodesiense T.cruzi

    Sleeping sickness Chagas’ disease


    Transmitted through Transmitted through
    Bite of Glossina (tsetse fly) Bite of Triatoma (winged bug)
    Geographical Distribution of African Trypanosomiasis

    G.palpalis G.morsitans
    In West Africa In East Africa
    Trypanosoma brucei causing Sleeping Sickness
    West Africa East Africa
    T.brucei gambiense T.brucei rhodesiense

    Less plentiful More plentiful


    Cannot live in lab animals Can live in lab animals
    Nucleus is
    shifted posteriorly
    Reservoir host: Reservoir host:
    goats, cattle & pigs wild game animals
    Transmitted by: G.palpalis Transmitted by: G.morsitans
    Mechanism of disease transmission by Glossina
    Trypomastigotes Diagnostic
    (polymorphic trypanosomes) stage
    12-42µ
    Bite of ♂ & ♀ Glossina
    3 weeks
    Salivary
    gland Epimastigote

    Full of short
    stumpy metacyclic
    trypanosomes
    Infective stage
    Biological
    transmission
    Pathogenesis and Clinical Picture
    Incubation period (2 weeks)
    Trypanosoma chancre (at the site of bite)
    Via lymphatics: enlarged lymph nodes especially
    posterior cervical region. (Winterbottom sign)
    Via blood stream: headache, fever, muscle & joint
    pain, irregular erythematous rash.
    Invasion of bone marrow (hypoplastic anaemia)
    Enlarged liver & spleen, generalized weakness.
    ‫ال مبااله‬
    Invasion of CNS: severe headache, mental apathy,
    slow speech, deep sleep, coma & death
    In East African Trypanosomiasis:
    Disease runs more rapid & fatal course
    Trypanosoma chancre Winterbottom’s sign

    Emaciation
    ‫جلد على عظم‬

    Coma before death


    Diagnosis
    1- Clinical picture: Chancre, Winterbottom’s sign, Headache, apathy

    2- Demonstration of trypanosomes:
    chancre
    In aspirate Lymph node
    from Blood or CSF
    - Microscopic examination of
    unstained or stained blood films Trypanosoma in
    stained blood film

    - Culture on suitable medium


    Epimastigote form

    - Animal inoculation
    Diagnosis
    3- Serological test:
    Increased total IgM level in serum due to antigenic variation
    of the surface coat of the parasite.

    Trypanosome posses genes that code for about 1000 variant


    forms of their surface glycoproteins. Switch to a different variant
    produces a new generation not susceptible to attack by
    immune factors specific to the previous generation.

    Trypanosomes can evade(‫ )تهرب‬the immune system


    Trypanosoma cruzi causing Chagas’ disease
    Prominent kinetoplast Winged bug
    Kissing bug
    Patient’s Triatoma or
    RBCs Rhodnius

    Trypanosoma
    cruzi
    C-shaped
    Mechanism of disease transmission by winged bug
    Cyclopropagative T.cruzi in human blood
    transmission

    Alimentary
    canal of Amastigote
    bug form

    Short stumpy Epimastigote


    metacyclic form
    trypanosomes
    (infective stage)
    Pass out with faeces
    Mode of infection

    Mainly by
    ‫خدوش بالجلد‬
    Contamination of skin abrasion
    by winged bug feces

    Rarely by
    infected blood transfusion
    Through infected mother’s milk
    the placenta
    Pathogenesis and Clinical Picture
    I- Acute Form
    Chagoma occurs at the site of bite.
    Parasite reaches regional lymph nodes
    To
    Blood
    To
    Organs and tissues
    Fever, enlarged lymph nodes, skin rash,
    enlarged liver & spleen.
    Romana’s sign may occur (conjunctivitis)
    Meningoencephalitis, heart failure
    Death or pass to chronic form
    Pathogenesis and Clinical Picture
    II- Chronic form
    Parasite produces antigens similar to Amastigote form
    patient’s self antigens: of T.cruzi
    The body produces auto-antibodies
    that cause damage to:
     Heart muscle fibres:
    congestive heart failure.
     Oesophageal muscle fibres:
    megaoesophagus and dysphagia.

     Colon muscle fibres:


    megacolon and constipation.
     CNS or thyroid gland
    Exacerbation of infection in
    immunosuppressed patients.
    Diagnosis
    Finding the parasite in:
    Blood film (C-shaped T.cruzi)
    Biopsy from lymph node, liver or spleen
    (amastigotes)
    Culture (epimastigotes)

    Xenodiagnosis

    Serological tests
    Cruzin test (I.D.)
    Molecular techniques
    Treatment
    Sleeping Sickness Chagas Disease

    In early stage of the disease:


    Pentamidine OR Suramin
    Nifurtimox
    In late stages of the disease:
    OR
    Tryparsamide Primaquine

    For both early and late stages


    of the disease:
    Ornidyl
    Control

    Sleeping Sickness Chagas’ disease

    Treatment of patients Treatment of patients

    Control of vectors Control of vectors


    (Glossina) (Triatoma)

    Pentamidine as
    Elimination of reservoir
    prophylactic drug
    hosts
    M.C.Q.
    Protozoal infections that may cause fever and
    hepatosplenomegaly
    a- Visceral leishmaniasis
    b- African trypanosomiasis (sleeping sickness)
    c- American trypanosomiasis (Chagas’ disease)
    d- Non of the above
    e- All of the above
    Smear taken from the edge of oriental sore reveals:
    a- promastigote c- amastigote

    b- epimastigote d- trypomastigote
    M.C.Q.
    Protozoa causing conjunctivitis include:
    a- Trypanosoma cruzi
    b- T.brucei gambiense
    c- T.brucei rhodesiense
    d- Leishmania donovani

    Winterbottom’s sign is seen in:


    a- Cutaneous leishmaniasis
    b- Visceral leishmaniasis
    c- African trypanosomiasis
    d- American trypanosomiasis
    M.C.Q.

    In African trypanosomiasis, the infective stage is


    found in: Short stumpy metacyclic trypanosomes
    a- Saliva of Triatoma c- Stool of Triatoma
    b- Saliva of Glossina d- Stool of Glossina

    Posterior nuclear shift occurs in:


    a- Trypanosoma cruzi
    b- Trypanosoma gambiense
    c- Trypanosoma rhodesiense
    d- Trichomonas vaginalis
    M.C.Q.

    In chronic Chagas’ disease, the main lesions are in:


    a- Digestive and respiratory tracts.
    b- Heart and liver.
    c- Heart and digestive tract.
    d- Liver and spleen.

    Megacolon associated with Chagas’ disease:


    a- Is manifested by diarrhoea.
    b- Occurs early in the disease.
    c- Is due to oedema of the mucosa.
    d- Is associated with constipation.
    Compare between
    Romana’s sign Acanthamoeba affection
    of the eye
    Inflammation of the conjunctiva Inflammation of the cornea
    Ulceration

    Perforation
    Ocular pain & affection of vision
    Mode of infection
    Contamination of skin Occurs through corneal trauma
    abrasions by winged bug Exposure to contaminated water
    (Triatoma) faeces Wearing contaminated contact
    Short stumpy lenses
    metacyclic
    trypanosomes

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