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Trypanosoma Introduction 1- Extracellular in BLOOD & TISSUES West African Trypanosomiasis: 2- West African Trypanosomiasis: “ West African Sleeping Sickness”

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Presentation on theme: "Trypanosoma Introduction 1- Extracellular in BLOOD & TISSUES West African Trypanosomiasis: 2- West African Trypanosomiasis: “ West African Sleeping Sickness”"— Presentation transcript:

1 Trypanosoma Introduction 1- Extracellular in BLOOD & TISSUES West African Trypanosomiasis: 2- West African Trypanosomiasis: “ West African Sleeping Sickness” caused by T. brucei gambiense. East African Trypanosomiasis: 3- East African Trypanosomiasis: “ East African Sleeping Sickness” caused by T. brucei rhodesiense. Chronic form: 4- Chronic form: caused by T. brucei gambiense. While Acute Form Acute Form is caused by T. brucei rhodesiense. African Sleeping Sickness 5- African Sleeping Sickness is the 3 rd important parasitic disease globally after Malaria & Schistosomiasis West African Sleeping Sickness 6- West African Sleeping Sickness is in regions along East African Sleeping Sickness riverside while East African Sleeping Sickness is in Forest regions (Savannas). Dr. RAAFAT T. MOHAMED

2 Trypanosoma Trypanosomiasis American Trypanosomiasis East African Trypanosomiasis Transmitted by Causes T.brucei rhodesienseT.brucei gambienseT.cruzi Sleeping sicknessChagas’ disease West African Trypanosomiasis Glossina (tsetse fly)Triatoma (winged bug) Dr. RAAFAT T. MOHAMED

3 Trypanosoma Morphology Exist into 2 interchangeable forms: Trypomastigote Trypomastigote in Blood/ Lymph / tissue space of various organs & C.N.S is terminal & fatal Epimastigote Epimastigote in salivary gland of vector & Culture media. Trypomastigote Trypomastigote (Polymorphic Trypanosomes Spindle shaped – Central nucleus – free flagellum – undulating membrane. 3 forms 1- long Slender Form (30µ): active motile with free flagellum. 2- Short stumpy Form (15µ): sluggish without free flagellum. 3- Intermediate Form (20µ): with a short free flagellum. Dr. RAAFAT T. MOHAMED

4 Geographical Distribution of African Trypanosomiasis G.palpalis G.morsitans In West Africa In East Africa Dr. RAAFAT T. MOHAMED

5 Trypanosoma brucei causing Sleeping Sickness West AfricaEast Africa T.brucei gambienseT.brucei rhodesiense Less plentiful More plentiful Cannot live in lab animals Can live in lab animals Reservoir host: goats, cattle & pigs Reservoir host: wild game animals Transmitted by: G.palpalisTransmitted by: G.morsitans Nucleus is shifted posteriorly Dr. RAAFAT T. MOHAMED

6 Mechanism of disease transmission by Glossina Bite of ♂ & ♀ Glossina Trypomastigotes (polymorphic trypanosomes) Diagnostic stage 12-42µ Epimastigote Full of short stumpy metacyclic Trypomastigote 3 weeks Infective stage Biological transmission Salivary gland Dr. RAAFAT T. MOHAMED

7 African Trypanosomiasis life cycle Life cycle of Trypanosoma brucei gambiense & T. b. rhodesiense Dr. RAAFAT T. MOHAMED

8 African Trypanosomiasis life cycle Dr. RAAFAT T. MOHAMED

9 African Trypanosomiasis life cycle Dr. RAAFAT T. MOHAMED

10 severe headache, mental apathy, slow speech, deep sleep, coma & death Pathogenesis and Clinical Picture Incubation period (2 weeks) Trypanosoma chancre (at the site of bite) Via lymphatics: enlarged lymph nodes especially posterior cervical region. Via blood stream: headache, fever (fluctuating), muscle & joint pain, irregular erythematous rash. Invasion of bone marrow Enlarged liver & spleen, generalized weakness. Invasion of CNS: In East African Trypanosomiasis: Disease runs more rapid & fatal course (Winterbottom’s sign) (hypoplastic anaemia) Dr. RAAFAT T. MOHAMED

11 Winterbottom sign Coma before death Trypanosoma chancre Emaciation جلد على عظم Pathogenesis and Clinical Picture Dr. RAAFAT T. MOHAMED

12 Clinical Picture Progressive disease may lead to the following C.N.S manifestations:- 1- Insomnia أرق 2- Mood changes (dullness بلاهة / apathy لامباله) 3- Motor & Sensory Disorders: (Hyperesthesia فرط الحس / slurred speech كلام متداخل / abnormal gait مشيه غير طبيعية). 4- Convulsions5- Epilepsy داء الصرع Terminal stage: 1- Permanent Sleep. 2- 2ry Bacterial infection. 3- Coma & Death. Dr. RAAFAT T. MOHAMED

13 Diagnosis 1- Clinical picture 2- Demonstration of trypanosomes: - Microscopic examination of unstained or stained blood films - Culture on suitable medium ( N.N.N OR Weinmann’s media to detect Epimastigote) - Animal inoculation Polymorphic Trypanosomes N.B. in case of T.brucei rhodesiense injected in lab Animal produce a new form “Posterior Nucleus Shift” Dr. RAAFAT T. MOHAMED

14 Diagnosis C.S.F

15 Diagnosis 3- Serological test: antigenic variation 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 (SVG). Switch to a different variant produces a new generation not susceptible to attack by immune factors specific to the previous generation. Trypanosomes can evade(تهرب) the immune system Dr. RAAFAT T. MOHAMED زيادة مطردهWhy in African Trypanosomiasis infection, there is a sustained elevated IgM level ???????

16 Trypanosoma cruzi causing Chagas’ disease Triatoma or Rhodnius Prominent kinetoplast Kissing bug Winged bug Trypanosoma cruzi C-shaped Dr. RAAFAT T. MOHAMED

17 Trypanosoma cruzi Morphology Trypomastigote Trypomastigote (Monomorphic) Slender shaped (20µ) – Central nucleus – C or U-shaped –Free flagellum 1/3 body- Large bulging peripheral kinetoplast Amastigote Obligatory intracellular – mainly in cardiac & Skeletal muscles – Brain meninges – Nerve ganglia – cells of GIT …. etc Epimastigote Epimastigote (Vector only) Spindle shape– Kinetoplast anterior to central nucleus– Undulating membrane is short – terminal free flagellum Dr. RAAFAT T. MOHAMED

18 Mechanism of disease transmission by winged bug T.cruzi in human blood Epimastigote form Short stumpy metacyclic trypomastigote (infective stage) Pass out with faeces Cyclopropagative transmission Alimentary canal of bug Dr. RAAFAT T. MOHAMED


20 Mode of infection Contamination of skin abrasion (خدوش بالجلد) by winged bug faeces Cone nose Bug – kissing Bug –Assassin bug Mainly by Rarely by Through the placenta Through infected mother’s milk Through infected blood transfusion Dr. RAAFAT T. MOHAMED

21 Life cycle of Trypanosoma cruzi Dr. RAAFAT T. MOHAMED

22 Life cycle of Trypanosoma cruzi Dr. RAAFAT T. MOHAMED

23 To Pathogenesis and Clinical Picture I- Acute Form Chagoma Chagoma occurs at the site of bite. Parasite reaches regional lymph nodes Blood Organs and tissues To Fever, enlarged lymph nodes, skin rash, enlarged liver & spleen. Meningoencephalitis, heart failure Romana’s sign Romana’s sign ( Unilateral conjunctivitis appear suddenly together with oedema of upper & lower eye lids & cheek ) Death or pass to Chronic form Dr. RAAFAT T. MOHAMED

24 Pathogenesis and Clinical Picture II- Chronic form Parasite produces antigens similar to patient’s self antigens:  Heart muscle fibres: Amastigote form of T.cruzi congestive heart failure.  Oesophageal muscle fibres: عصر البلع megaoesophagus and dysphagia. Destruction of Auerbach’s plexus  Colon muscle fibres: megacolon and constipation.  CNS or thyroid gland Exacerbation of infection in immunosuppressed patients. The body produces auto-antibodies that cause damage to: Dr. RAAFAT T. MOHAMED

25 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 Dr. RAAFAT T. MOHAMED

26 Diagnosis (Xenodiagnosis) Highly efficient – demonstrate low level of parasite in blood Method: A Laboratory bred winged bug is starved for 2 weeks then fed on suspected patient’s blood – 30 days later, it faeces & gut examined for trypanosomes. Dr. RAAFAT T. MOHAMED

27 Diagnosis Romana’s sign Chagoma Trypomastigote Amastigote Winged Bug Dr. RAAFAT T. MOHAMED

28 Treatment In early stage of the disease: Pentamidine OR Suramin In late stages of the disease: Tryparsamide For both early and late stages of the disease: Eflornithine (DFMO) Ornidyl Nifurtimox -inhibits intracellular development. -Drug of choice in acute and early chronic OR Primaquine destroys Trypanosoma in blood Sleeping SicknessChagas Disease Dr. RAAFAT T. MOHAMED

29 Control Treatment of patients Control of vectors (Glossina) Pentamidine as prophylactic drug Treatment of patients Control of vectors (Triatoma) Elimination of reservoir hosts Sleeping Sickness Chagas’ disease Dr. RAAFAT T. MOHAMED

30 M.C.Q. 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: Protozoal infections that may cause fever and hepatosplenomegaly a- promastigote b- epimastigote c- amastigote d- trypomastigote Dr. RAAFAT T. MOHAMED

31 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: d- American trypanosomiasis c- African trypanosomiasis b- Visceral leishmaniasis a- Cutaneous leishmaniasis Dr. RAAFAT T. MOHAMED

32 M.C.Q. In African trypanosomiasis, the infective stage is found in: a- Saliva of Triatomac- 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 Short stumpy metacyclic trypanosomes Dr. RAAFAT T. MOHAMED

33 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. Dr. RAAFAT T. MOHAMED

34 Compare between Romana’s signAcanthamoeba affection of the eye Inflammation of the conjunctivaInflammation of the cornea Occurs through corneal trauma Exposure to contaminated water Wearing contaminated contact lenses Mode of infection Contamination of skin abrasions by winged bug (Triatoma) faeces Short stumpy metacyclic trypanosomes Ulceration Perforation Ocular pain & affection of vision Dr. RAAFAT T. MOHAMED

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