AB L1 Protazoa Flashcards
Protozoa are….
Diverse group of single celled ‘animal like’ eukaryotes
Protozoa are pro/Eukaryotes
Eukaryotes
Size of protozoa
2-100 microm
Protozoa are mostly fee-living or pathogens?
Mostly free living. Some are pathogens.
Where are protozoa most prevalent?
(sub)tropical regions
Protozoa act as intra or extracellular parasites?
Intracellular in the cells
Extracellular parasites in the blood, intestine, urogenital system
4 classifications of protozoa
Amoeba - move by pseudopodia
Flagellates - have flagella
Ciliates - have cilia (most not pathogenic)
Apicomplexa - have apical complex (all parasitic)
Malaria is what type of protozoa?
Sporozoa
Ways protozoa might spread
Insect-bourne, water-bourne
Toxoplasma is spread by …. and infects what cells
Food
Macrophages
Usually asymptomatic but can cause proplems in HIV or pregnancy, such a still birth
Malaria is caused by
Plasmodium
Plasmodium initially affects …. then….
liver then RBC
Why don’t we know much ab out numbers affected?
Rural areas, little reporting .
Most of these disease are on the neglected diseases list.
Malaria is mainly found in ….
Most deaths are in….
Tropical areas of Africa, Asia & South America
Most deaths in Africa (90%)
What population of the world is at risk of malaria?
40%
4 species of malaria that infect humans
P. falciparum
P. vivax
P. ovale
P. malariae
Which malaria organism is the most common and most severe cause of malaria
P. falciparum
Which malaria organism is the most common cause of malaria outside Africa?
P.vivax
Which malaria organism is the least common and most moderate form?
P. malariae
Transmission of malaria through….
female feeding mosquitoes (Anopheles sp.), injects saliva into the blood
When malaria enters the body it….
multiplies in the liver (two weeks) - development of gametes, then infects RBCs
Malaria parasites go through the reproductive phase in which organism?
the mosquito (liver cell reupture, merozite released, asexual reproduction in the RBC, gametes taken up into mosquito and they fuse in it)
(Uncomplicated) Symptoms of malaria
6-10h of
- cold stage (shivering)
- hot stage (fever)
- sweating stage
Also: headache, body ache, nausea, vomitting, weakness, enlarged spleen
How could you tell the type of infection? (2)
Different timings of the temp cycles or expert looking at cells under a microscope
Complicated symptoms with malaria (6)
Cerebral malaria - abnormal behaviour, seizure, coma Shock Anaemea (due to haemolysis) Pulmonary oedema Liver failure Spleen rupture
What may cause spleen rupture?
RBC becomes sticky and proteins gets into the membrane, this prevents them being cleared up by the spleen.
ABCD for travellers
Awareness of risk
Bite prevention
Chemoprophylaxis (there is usually but not always a drug without resistance possible)
Diagnosis and treatment
Drug of choice for areas with NO resistance (2)
Chloroquine OR Proguanil
Drug of choice for areas with LITTLE resistance
Chloroquine AND Proguanil
Drug of choice for areas with RESISTANCE
Mefloquinin
Doxycyclin
Atovaquone-proguanil (malerone)
How to diagnose malaria?
- symptoms overlap with other diseases so…
- blood smear
- rapid detection tests
- Others: PCR, antibody detection, MS (expensive and need expertise)
Advantages/disadvantage of blood smear?
Cheap but labor intensive and requires expertise
Advantages/disadvantage of rapid detection test?
Fast/can be used in the field BUT
limited sensitivity
Rapid detection test detects…. (2)
antigens/enzymes
Immunochromatograph tech (rapid detection test)
sample (blood+buffer) mixes with labelled detection antibody on strip,
migrates through capillary action,
dark line appears where high conc of antibody
Labelling antibody made of (2)
gold or dye
dectection strip made of
nitrocellulose
there maybe extra lines on the rapid diagnostic test for…
control
more sensitive to detect a low level
different types of malaria
Treatment of malaria divided by
P. falciparum or other
Treatment of P.falciparumL (3)
- quinine followed by doxycycline or clindamycin
- atovaquone-proguanil
- arthemether-lumefantrine
Treatment for other types of malaria
Chloroquinine followed by
primaquinine (for p vivaz and p ovale)
Malaria may lay dormant for….
half a year
Chinese herbal medicine that helps malaria
Artemisin-based combination therapy
Good things about artimisin?
active against all 4 species
rapid parasite clearance/resolution of symptoms
How does artemesin work?
acts on the blood stage so reduces gamete carriage and hence transmission
disadvantage of artemsin
10x more expensive than other drugs
Artemesin is extracted from
wormwood. there is little supply and some resistance too.
Do we know how most antimalarials work? but we think ……… happens
no.
They prevent the polymerisation of haem and this free haem is toxic to the parasite
Why is artemisin used in combination
short half life
3 vaccine options
attenuated microbes - hard
killed microbes - hard
subunit vaccines - response not as good
the problem with malaria vaccine (2)
difficult to grow enough pathogen for attenuation of killed vaccine.
Also there are no good animal models
is there natural immunity
yes but this hasn’t told us much
some antigens exhibit genetic polymorphism
some antigens show temporal switching of expression (only expressed at one stage in the cycle)
Most promiseing malaria vaccine is called
RTS,S (mosquirix)
Seems to work but waiting for results later this year
What are the components of RTS,S (mosquirix)
Cicumsprozoite protein (cell surface protein)
Central repeat domain and c terminal region (has the T cell epitope)
Fuse to Hep B surface antigen
Expressed with free Hep B surface antigen
