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

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

3. Trypanosoma Morphology Exist into 2 interchangeable forms:
Trypomastigote in Blood/ Lymph / tissue space of various organs &
C.N.S is terminal & fatal
Epimastigote in salivary gland of vector & Culture media.
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 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: goats, cattle & pigs
Reservoir host: wild game animals
Transmitted by: G.palpalis
Transmitted by: G.morsitans
Dr. RAAFAT T. MOHAMED

6. Mechanism of disease transmission by Glossina
Trypomastigotes (polymorphic trypanosomes)
Diagnostic stage
12-42µ
Bite of ♂ & ♀ Glossina
3 weeks
Salivary gland
Epimastigote
Full of short stumpy metacyclic Trypomastigote
Infective stage
Biological transmission
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. 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’s sign)
Via blood stream: headache, fever(fluctuating), muscle & joint pain, irregular erythematous rash.
Invasion of bone marrow
(hypoplastic anaemia)
Enlarged liver & spleen, generalized weakness.
Invasion of CNS:
severe headache, mental apathy, slow speech, deep sleep, coma & death
In East African Trypanosomiasis:
Disease runs more rapid & fatal course
Dr. RAAFAT T. MOHAMED

11. Pathogenesis and Clinical Picture
Winterbottom sign
Trypanosoma chancre
Emaciation جلد على عظم
Coma before death
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- Convulsions
5- Epilepsy داء الصرع
Terminal stage:
1- Permanent Sleep.
2- 2ry Bacterial infection.
3- Coma & Death.
Dr. RAAFAT T. MOHAMED

13. - Microscopic examination of unstained or stained blood films
Diagnosis
1- Clinical picture
2- Demonstration of trypanosomes:
Polymorphic 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
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
Dr. RAAFAT T. MOHAMED

15. Trypanosomes can evade(تهرب) the immune system
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 (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
زيادة مطردهWhy in African Trypanosomiasis infection, there is a sustained elevated IgM level ???????
Dr. RAAFAT T. MOHAMED

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

17. Trypanosoma cruzi Morphology Trypomastigote (Monomorphic) Amastigote
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 (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
Cyclopropagative transmission
Alimentary canal of bug
Short stumpy metacyclic trypomastigote (infective stage)
Epimastigote form
Pass out with faeces
Dr. RAAFAT T. MOHAMED

19. AMERICAN TRYPANOSOMIASIS
LIFE CYCLE OF Trypanosoma cruzi
Dr. RAAFAT T. MOHAMED

20. Mode of infection Mainly by
Contamination of skin abrasion (خدوش بالجلد) by winged bug faeces
Cone nose Bug – kissing Bug –Assassin bug
Rarely by
Through infected blood transfusion
Through infected mother’s milk
Through the placenta
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. 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 (Unilateral conjunctivitis appear suddenly together with oedema of upper & lower eye lids & cheek)
Meningoencephalitis, heart failure
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:
Amastigote form of T.cruzi
The body produces auto-antibodies that cause damage to:
Heart muscle fibres:
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.
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 Winged Bug Trypomastigote Romana’s sign Chagoma Amastigote
Dr. RAAFAT T. MOHAMED

28. Treatment Sleeping Sickness Chagas Disease Pentamidine OR Suramin
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
Dr. RAAFAT T. MOHAMED

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

30. Protozoal infections that may cause fever and hepatosplenomegaly
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
d- trypomastigote
b- epimastigote
Dr. RAAFAT T. MOHAMED

31. Protozoa causing conjunctivitis include: a- Trypanosoma cruzi
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
Dr. RAAFAT T. MOHAMED

32. Short stumpy metacyclic trypanosomes
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
Dr. RAAFAT T. MOHAMED

33. In chronic Chagas’ disease, the main lesions are in:
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 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 abrasions by winged bug (Triatoma) faeces
Occurs through corneal trauma
Exposure to contaminated water
Wearing contaminated contact lenses
Short stumpy metacyclic trypanosomes
Dr. RAAFAT T. MOHAMED