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General issues of Vaccine
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General issues of Tropical med.
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General issues of Travel med.
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Trematode (fluke, distoma)
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Pathogen
- Trypanosoma brucei
- Trypanosoma brucei gambiense
- Trypanosoma brucei rhodesiense
Morphology
- amastigote
- promastigote
- epimastigote
- trypomastigote
- nucleus, kintoplast, undulating membrane, flagellum
Life cycle
- T. brucei group don't infect human cells
- T. cruzi needs to infect human cells to multiply
Vector
- tsetse fly
- genus Glossina
- adult 6-15 mm long
Epidemiology
- >70% of cases in recent 10 years are reported from DRC
- 10-100 new cases in a year in Angola, Central African Republic, Chad, Congo Republic, Gabon, Guinea, Malawi and South Sudan
African trypanosomiasis
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Trypanosoma brucei gambiense
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Trypanosoma burcei rhodesiense
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Distribution
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- West Africa
- Broader area to the west of Great Rift Valley
- In 24 countries
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- East Africa
- Limited to the east of Great Rift Valley
- In 13 countries
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Vector
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- Glossina palpalis
- In humid environment
- Anthroponotic; human-to-human
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- Glossina morsitans
- In dryer environment
- Mainly bite animals
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Infectivity
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- Mainly infect to human
- Adapted to human, leading to relatively slow and mild disease progression
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- Mainly infect to animals
- Adapted to animals, leading to relatively rapid progress of disease
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Human infection
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- 98% of total cases
- Chronic infection
- Incubation months to years
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- 2% of total cases
- Acute infection
- Incubation weeks to months
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Trypanosoma brucei brucei
- Trypanosomiasis of stock and wild animals
- no human infection
pathogenesis
- trypanosomal chancre after tsetse fly bite
- acute hemolymphatic stage
- fever, headache, myalgia, arthralgia, lymphadenopathy, splenomegaly
- chronic meningoencephalitic stage
- headache, alteration of mental status, coma
- more acute by T. brucei rhodesiense, slower by T. brucei gambiense
diagnosis
- serology
- card agglutination test for trypanosomiasis (CATT)
- mass population screening
- low sensitivity/specificity
- molecular
- microscopy
- chancre fluid, blood, lymph node aspirate, CSF
- centrifugation and examination of buffy coat
- wet praparation for motile trypanosoma
- Giemsa stain (with fixed)
define the clinical stage of rhodesiense
- lumbar puncture
- CSF WBC > 5 cell/mm3 stage 2
treatment
- should commence in earlier stage
- difficult to treat in CNS involvement
- acute stage
- suramin > pentamidine
- suramin side effects
- 90% urticaria
- 50% adrenal cortical damage
- peripheral neuropathy - axonal or demyelinating
- renal dysfunction
- chronic stage
- melarsoprol (Mel B)
- only for T. b. rhodesiense
- eflornithine (DL-a-difluoromethilornithine; DFMO)
- nifurtimox-eflornithine; NECT
- both stage
- fexinidazole
- only for T. b. gambiense
- should be administered within 30 min. after solid meal