Blood+Tissue Protozoa Flashcards
List some blood and tissue protozoal diseases
Malaria, Toxoplasma, Trypanosoma, Leishmania
Malaria parasite
Plasmodium spp:
P. falciparum, P. vivax, P. ovale, P. malariae, P.
Knowlesii
(similar life cycles)
Malaria protozoan carrier
Anopheles mosquito
Malaria transmission
Person to person via mosquito
Shared needles by drug users
Blood transfusion
Organ transplant
Define - Epidemic determinant factors
Environmental factors that help the parasite to survive
Epidemic determinant factors for Plasmodium spp
(a) Drought
(b) Elevated drug resistance
(c) Abnormal temperature
(d) Land pattern changes
(e) High malnutrition rates
How is drought an epidemic determinant factor for Plasmodium spp
Rainfall in usually dry area creates breeding sites
How is elevated drug resistance an epidemic determinant factor for Plasmodium spp
No effective antiparasitic means more spread of Plasmodium spp.
How is abnormal temp an epidemic determinant factor for Plasmodium spp
hot temp -climate change allows for optimal survival of mosquito species
How is land pattern changes an epidemic determinant factor for Plasmodium spp
People moving from country-town, less trees due to buildings, carbon emissions
How is high malnutrition rates an epidemic determinant factor for Plasmodium spp
anorexic + obese =malnourished b/c abnormal nutrition, easier for parasite to proliferate in malnourished host
Does each type of pathogen have virulence factors?
What makes it difficult for pathogens to invade?
Each pathogen has virulence factors - fungi, parasite, bacteria, virus
-If the host factors (normal flora etc) are intact it is difficult for pathogens to invade and overwhelm
Virulence factors of Plasmodium spp
-Antigenic variations (antigens on spp can change; fool host cell into thinking it isn’t a foreign pathogen)
- Cytoadherence of infected rbc (site adherence factor, allows pathogen infect rbc
- > RBC well protected but spp overcome this
Malaria life cycle
- Sporogenic cycle -> mosquito ingests gametocytes (male+female) via human
- Gametocytes form macro and microgametes.
- Develop ookinetes then oocysts,
- They get to cavity of mosquito, burst open and releases sporozoites
- Sporozoites in saliva which passes to human via bite (infective stage)
- Sporozoites move to liver then form another cycle called exo-erythrocytic cycle.
- Takes place outside rbcs.
- Schizont (mature sporozoite) ruptures then goes to rbcs.
- Now Erythrocitic cycle. (rbc stage)
- It will enter rbcs, rbc will rupture and schizonts go to liver or blood.
P vivax and P ovale can remain dormant as hypnozoites in liver.
Lab ID - Malaria
Microscopy: Thick & Thin Blood film staining
Stained with Giemsa
-looking for the small trophozoites (ring) in the cells or the banana shaped gametocytes.
Gold std. id method
(purple capped tube - malaria)
Serological methods: to detect Abs is only used
for screening in blood donors. Ab may not be
present in acute infection.
Fluorescent dye technique - Malaria ID
Fluorescent dyes that stain nucleic acids have been used in the detection of blood parasites.
- Kawamoto technique - blood smears on a slide are stained with acridine orange and examined with either a fluorescence microscope or a light microscope adapted with an interference filter system.
- Differential staining of nuclear DNA in green and of cytoplasmic RNA in red, which allows recognition of the parasites.
Additional Diagnostic Tests - Malaria
Ag detection (rapid test):
(a) Plasmodium lactate dehydrogenase-pLDH,
(b) Histidine rich parasite-HRP2,
(c) Pan-Plasmodium LDH,
(d) Quantitative buffy coat-QBC
Molecular tests: PCR
Does Quantitative Buffy Coat Method have good sensitivity in detecting malarial parasites?
The QBC method is reported to have a good sensitivity for detection of malaria parasites.
Treatment for blood and tissue protozoa
Tissue Schizonticides: - Primaquine
• Blood Schizonticides: - Chloroquine-susceptible -
Chloroquine phosphate; Chloroquine-resistant -
Mefloquine, Quinine sulfate, Pyremethamine-
Sulfadoxine; Doxycycline, Halofantrine, Artemisinin
(Quinghaosu), Atovaquone-proguanil
•Gametocytocidal: - Quinidine gluconate, Artesunate,
Quinine dihydrochloride, Artemether
Malaria species - range in severity of anemia and list symptoms
Anaemia usually results mildly in P. ovale, moderately in P. vivax and P. malariae and very severe in P. falciparum.
Symptoms:
- Quotidian/recurring fever, nausea, vomiting,
Malaria - complications
- CNS involvement (cerebral malaria) - may or may not be in P. vivax, P. ovale or P. malariae type but in P. falciparum, there is and usually very severe.
- Nephrotic syndrome does not occur in P. ovale, may occur in P. vivax, mildly in P. falciparum but usually always in P. malariae
• Hypoglycaemia; Pulmonary oedema & Respiratory distress;
Metabolic (Lactic) Acidosis; Malaria of Pregnancy
Malaria prevention
Chemoprophylaxis (killing effect against parasite, either within the erythrocytes/ hepatocytes)
Chloroquine phosphate, Mefloquine,
Doxycycline, Atovaquone-proguanil
• PPE & Avoidance: Protective clothing, eradication of
mosquitoes and their breeding sites, use of mesh in
houses, use of insect repellants; health education
• Vaccines – still being developed
Parasitic flagellate protozan diseases from family Trypanosomatidae
Trypanosoma and Leishmania
Why is Trypanosoma and Leishmania called hemoflagellates?
• Because these protozoans require hematin obtained
from blood hemoglobin for aerobic respiration
