L14 Protozoa Flashcards
1
Q
what are protozoa
A
anything unicellular and non-photosynthetic that isnt a fungus
2
Q
what is the protozoa group
A
position of root unclear
not a natural (true) evolutionary group
3
Q
what are the 2 protozoan phyla important for human parasitology
A
apicomplexa
euglenozoa (inc kinetoplastida)
4
Q
which protozoan phyla contains the most important parasites of man
A
apicomplexa
5
Q
what are the apicomplexa parasites
A
plasmodium
toxoplasma
6
Q
what is the plasmodium vertebrate host habitat
A
intracellular
erythrocyte and hepatocyte
7
Q
what is the toxoplasma vertebrate host habitat
A
intracellular
macrophage and other cell types
8
Q
what are the kinetoplastida parasites
A
leishmania
american trypanosomes
african trypanosomes
9
Q
what is the leishmania vertebrate host habitat
A
intracellular
macrophage
10
Q
what is the american trypanosomes vertebrate host habitat
A
intracellular - several cell types
and extracellular
11
Q
what is the african trypanosomes vertebrate host habitat
A
extracellular
12
Q
what is the mode of transmission for plasmodium
A
vector born mosquito
13
Q
what is the mode of transmission for toxoplasma
A
ingestion of cysts
14
Q
what is the mode of transmission for leishmania
A
vector born sandfly
15
Q
what is the mode of transmission for american trypanosomes
A
vector born reduviid bug
16
Q
what is the mode of transmission for african trypanosomes
A
vector born tsetse fly
17
Q
what are the diplomonad parasites
A
giardia
18
Q
what are the parabasalid parasites
A
trichomonas
19
Q
what are the archamoeba parasites
A
entamoeba
20
Q
what is the diplomonad vertebrate host habitat
A
extracellular
21
Q
what is the parabasalid vertebrate host habitat
A
extracellular
22
Q
what is the archamoeba vertebrate host habitat
A
extracellular
23
Q
what is the mode of transmission for diplomonad
A
ingestion of cysts
24
Q
what is the mode of transmission for parabasalid
A
sexual transmission
25
what is the mode of transmission for archamoeba
ingestion of cysts
26
what is the apicomplexan phylogeny
single complex group
diversified into lots of different classes
all parasites
27
what is the cell form for apicomplexa
polarised
28
what is the invasive lifecycle of apicomplexa like
specialised apical complex
| polar cell with pointed end has specialised cells fro invasion
29
what is the apicoplast
remnant of photosynthetic past
30
how is malaria transmitted
by female Anopheles
31
how many plasmodium infect humans
5/6
32
what is the invasion cycle of mosquito like
3 invasion cycles: liver, RBC, potentially escape cycle when taken up by mosquito undergo sexual change (back to liver)
33
what is the decision stage in mosquito life cycle
re-enter replicative intra-erythrocytic cycle
OR
make gametes for transmission
34
what is the invasion cycle of cryptosporidium like
direct - simple
can reinvade gut cells multiple times
OR
exit - sexual cycle make eggs, taken back up again
35
how is cryptosporidium transmitted
contaminated water
36
what does cryptosporidium cause
```
usually mild (diarrhea)
self resolving
if are immunocompromised = chronic fatal illness
```
37
what are the cryptosporidium that cause human disease
Cryptosporidium parvum
Cryptosporidium hominus
(plus C.felis, C.meleagridis, C.canis, C.muris)
38
what is the invasion cycle of toxoplasma gondii
prey infected ingesting eggs
invasion in gut or escape and invade other parts of body
sexual cycle only in predator
part in prey and another in predator due to evolutionary pressure, parasite can find a niche to specialise into it
39
which lifecycle is most like the apicomplexans ancestral one
cyrotosporidium or american trypanosome
40
what is the definitive toxoplasma gondii host
cats
41
what is the effect of toxoplasma gondii infection
prey have brains cysts alter behaviour (increasing transmission rate)
- impaired motor performance
- increased risk-taking
42
what is the kinetoplastid cell like
```
single copy organelles
single mitochondrion
single kinetoplast
flagellum
glycosomes
```
43
what makes it a kinetoplastid
kinetoplast
44
how is american trypanosomiasis transmitted
hematophagous bugs from the family Reduviidae
45
where is american trypanosomiasis prevalent
south and central america
46
what is the american trypanosome lifecycle
simple
infect gut of bug
transmitted in faeces in form that invades humans
invades human tissue, lose flagellum, non motile
divide in cells, burst out in flagellate form, infect new cells
47
what is the decision stage of the american trypanosome lifecycle
restart cycle
OR
become specialised form to infect and complete cycle in bug
48
what is the acute phase effects of american trypanosome
fever
hepatosplenomegaly
10% mortality
49
what are the chronic effects of american trypanosome
cardiomyopathy
nerve degeneration
megaesophagus
megacolon
50
what is american trypanosomiasis known as
chagas' disease
51
what is human african trypanosomiasis known as
sleeping sickness
52
what is the lifecycle of human african trypanosome
duplicate in insect gut
invasive form transmitted in bite
forms in blood to divide or form a form that it primed for transmission
53
how does human african trypanosome move
highly motile
54
what is the lifecycle of leishmania
divide in gut
migrate to saliva gland
inject to human host
division in human host and gets into other cells – intracellular
55
what are the leishmania manifestations
cutaneous
mucocutaneous
visceral or kala-azar
56
what causes cutaneous leishmania
L. major & L. tropica
57
what is cutaneous leishmania
skin ulcers at the site of bite, with varied number of amastigote forms in it
58
what causes mucocutaneous leishmania
L. braziliensis & L. mexicana
59
what is mucocutaneous leishmania
ulcers of the skin, mouth and nose
60
where does mucocutaneous leishmania occur
South and Central America up to Texas, US
61
what causes visceral leishmania
L. donovani
62
what does visceral leshimania cause
```
fever
anaemia
enlarged liver and spleen
bleeding
breathing difficulty
```
63
what is the survival of visceral leishmania
6-12 months
64
bite site for leishmania transmission - following stages of invasion
saliva contains vasodilators
sand fly co-transmits bacteria and viruses
bite damages tissue, triggers neutrophil recruitment
saliva increases migration of inflammatory cells, enhancing interaction of leishmania with host cells
65
leishmania mechanism of host cell invasion
use cell surface molecules and secretory to stimulate engulfment
need to prevent phagolysosome developing too far down lysosomal pathway and killing it – lesihmainia modify the phagolysosome behavior so it provides them with nutrients and doesn’t kill them
they grow and burst out to infect
66
how does leishmania actively invade
no active invasion machinery
67
how does leishmania survive intracellularly
intracellular amastigotes tolerate low pH and are resistant to hydrolases
inhibition of fusion with late endosomes
interfere with host-cell signalling
68
effect of leishmania on phagosome
no major modification
69
how does plasmodium change RBC
modifies RBC surface it infects – individual knobs made by parasite deliberately
made by parasite secretion PfEMP1 (for P. falciparum)
70
what does PfEMP1 do
'rosetting’ of erythrocytes
71
how does PfEMP1 do its function
binds to Duffy antigen
72
what is the role of the spleen
filters blood
removes senescent erythrocytes
metabolises haemoglobin and recycles iron
73
where is the late stage plasmodium infected RBCs detected
in the spleen
74
how does the parasite avoid spleen removal
rosetting – protects certain amount of the RBC surface, when goes through spleen not as obvious = reduced detection
cytoadherence (clumping) prevents parasites traveling through spleen
75
what is PfEMP1 important for
immunity and disease
76
what is the PfEMP1 gene like
conserved intracellular C-terminal tail
| diverse extracellular region
77
how do PfEMP1 vary
extracellular parts differ considerably = different binding properties and different recognition by immune system
78
what is seen in endemic areas of plasmodium falciparum infection
exposure to parasite very early in life
early exposure results in most deaths and greatest disease
= either develop resistance or die
79
what is acquired immunity
depends on antibody-antigen interaction
80
what is antigenic variation
a system employed by various pathogens to evade acquired immunity
constantly change surface that they expose to immune system so can live extracellularly in blood system
81
why is antigenic variation important
stands in the way of vaccination
82
what is the trypanosoma brucei cell like in the bloodstream
covered in a coat of variant surface glycoprotein (VSG)
83
why is VSG immunogenic
10 million copies form a monolayer
| periodic change in immunological identity - switching VSG coat
84
how do protozoan parasites 'specialise' in immune evasion
1. hide away
- intracellular
- cytoadherence/sequestration (plasmodium)
2. antigenic variation (plasmdoium, giardia, trypanosoma brucei)
85
which are the intracellular protozoan parasites
apicomplexa
trypanosoma cruzi
leishmania spp.
