protists and human disease Flashcards
diseases caused by apicomplexa
malaria and cryptococcoidis, toxoplasmosis
diseases caused by amoebazoa
entomoebas cause amoebiasis
diseases caused by excavates
parabasilidis e.g. trichomonad vaginalis causes trichomoniasis
diplomonads e.g. giardia lamblia causes giardiasis
kinetoplastids e.g. trypanosoma
trypanosoma cruzi
chagas disease
vector of chagas
triatomine bugs
trypomastigote
found in bloodstream of infected vertebrates
epimastigote
found in the insect vector
amastigote
intracellular dividing form in the cytoplasm of vertebrate cells
host localisation of chagas
intracellular in: cardiac muscle smooth muscle autonomic nerves macrophages
immune invasion of chagas
intracellular multiplication and immune response is primarily cellular (t-cells)
can grow within macrophages
trypanosoma brucei
african sleep sickness
trypanosoma brucei vector
tsetse fly
west sleeping sickness
trypanosoma brucei GAMBIENSE
invades CNS and chronic
east sleeping sickness
trypanosoma brucei RHODESIENSE
organ damage and acute
host invasion of T. brucei
inoculated by tsetse fly blood lymph lymph nodes CSF brain
Host localisation of sleeping sickness
intercellular
sleeping sickness immune invasion
parasite presents VAT
coat made up of VSG (highly packed prevents immune recognition and protects against lytic compounds)
unique to african trypanosomas
immune invasion of T brucei
VSG one coat and VAT1
host produces antibodies against VAT1 and destroys parasites
VSG 2 coat produces VAT2 but host has no antibodies against VAT 2 so it increases
procyclin
single surface antigen expressed by tsetse fly gut trypanosomes
where is first VSG produced?
in salivary gland produced by infective metacyclic trypomastigote
what is needed for VSG’s to be expressed?
must be located in telomeric expression sites
how many expressions sites do blood stream forms of parasite t.brucei have?
20
how many VSGs can be expressed at a time?
one, there is only one active expression site
what leads to antigenic variation?
in situ switch (use of different VSG expression site) Gene conversion (DNA recombination in active expression site)
sleeping sickness acute form
haematolymphatic phase
sleeping sickness chronic form
meningoencephalitic phase
T.cruzi life cycle summary
ingestion of parasites with blood meal
defecation of parasites near wound
T.brucei life cycle summary
ingestion of parasites with blood meal
inoculation of parasites in saliva by tsetse fly
