African Trypanosomiasis Flashcards
Trypanosomes order
Kinetoplastids
Trypanosomes family
Trypanosomatidae
Trypanosomes genus
Trypanosoma
African sleeping sickness
African trypanosomiasis
2 subspecies
T. brucei rhodesiense and T. brucei gambiense
American trypanosomiasis
T. cruzi or Chagas disease
East African Tryp
T. brucei rhodesiense = acute
West African Tryp
T. brucei gambiense = chronic, slowly progressing
T. brucei brucei
infects wild and domestic animals (NOT HUMANS) and causes a disease called nagana
T or F. African tryps are protozoan hemoflagellates
T! but do not have intracellular form and multiply as trypomastigotes that circulate in the mammalian bloodstream and other extracell spaces
T or F. 2 subspecies of T. brucei are morphologically distinguishable
F! not distinguishable but american and african can be told apart
vector of African sleeping disease
tsetse fly
- endemic disease; only in sub-Saharan Africa
T or F. T. brucei rhodesiense is more common
F! T. b. gambiense more common = 24 countries in west and central Africa; more than 95% cases
transmission of African sleeping disease
- VECTOR = tsetse flies
- transfusion
- mother to child
- other blood sucking insect
- lab accidents
- sexual contact
Glossina flies
- tsetse
- obligate parasites
- live on blood of vertebrate animals
- fold their wings completely so one wing rests directly on top of other over their abdomen
- long proboscis; attached by distinct bulb of the bottom of their head
T or F. T. b. gambiense infect humans
T!
T. b. rhodiense = animals
stage 1 pathogenesis of T. brucei
- bite = chancre
- hemolypmhatic stage
- interstitial multiplication of trypanosomes within chancre = intense mononuclear cell rxn to parasites
- parasites go regional lymph nodes = proliferate = inflammatory response
- go to lymphatics then to bloodstream = multiplication
stage 2 pathogenesis of T. brucei
- reaches brain and meninges = meningoencephalitis = frontal lobe, pons, medulla
- edema and hemorrhages
- infiltration of CNS w mononuclear cells (plasma cells, lymphocytes, Mott cells)
- CSG = increased pressure, total protein, monocytes and eos
unique feature of African trypanosomes
- can change surface coat of outer membrane of trypomastigote
= evades host immune response - 1000 different variant surface glycoprotein (VSG)
- changes about 5-7 days
= successive waves of parasitemia every 7-14 days
how long does T.b. gambiense last
months to years
- intermittent fever, posterior cervical lymphadenopathy (Winterbottom sign)
how long does T.b. rhodiense last
days to weeks
- high fever, thrombocytopenia, hepatitis, myocarditis, cutaneous chancre, anemia
Winterbottom’s sign
T. b. gambiense
primary reservoir of T. b. rhod
cattle, antelope, domestic pigs and dogs (accidental)
how to diagnose T. b. rhod
microscopy
- blood = high parasitemia
- lymph node fluid
- chancre biopsy, aspirate
- CSF (MUST!)
how to diagnose T. b. gamb
- multiple lymphadenopathy
= lymph node aspirate (usually posterior cervical node) - blood
- chancre aspirate
- CSF (MUST!)
- serology
- CATT ( card agglutination test for trypanosomes)
- ELISA
- IFA (indirect fluorescent antibody assays)
