Plasmodium spp. I Flashcards
What are the four major plasmodium spp.?
- falciparum
- vivax
- ovale
- malariae
*knowlesi also reported in southeast asia
Plasmodium spp. are found in tropics and subtropics worldwide, which species is confined to western Africa?
P. ovale
How are ALL malaria species transmitted?
Anopheles mosquitos
-Females
What is the mechanisms of infections following mosquito bite (anopheles, female)? (3)
- Sporozoites injected into blood stream and go to liver and proliferate (Exoerythrocytic schizogony)
- Schizonts rupture and release merozoites into bloodstream
- Merozoites infect RBCs to initiate erythrocytic schizogony
In endemic areas who is at greatest risk of death?
Pregnant and Young children
-Relative immunity develops in those who survive childhood
*outside of endemic areas, all age groups are equally susceptible
After inoculation, when does malaria usually present?
1-4 weeks
What are the initial symptoms?
- 1st week asymptomatic
- initial stages of erythrocytic schizogony produce disorganized and vague symptoms
What happens within weeks of infection?
Schizogony becomes synchronized and produce fever cycles
What does full blown malaria look like?
- Symptoms are paroxysmal, lasting 6-12 hours
- Intermittent intravascular hemolysis
Species specific clinical features:
-Fever spikes every 48 hours (3)
- P. ovale
- P. vivax
- P. falciparum
Species specific clinical features:
-Most lethal
P. falciparum
-“malignant tertian malaria”
Species specific clinical features:
-Fever spikes every 72 hours
P. malariae
-quartan fever)
Species specific clinical features:
-Nephrotic syndrome
P. malariae
Species specific clinical features:
-CNS involvement
P. falciparum
Species specific clinical features:
-Hemosiderinuria, hemoglobinuria, and renal failure
P. falciparum (“blackwater fever”)
Species specific clinical features:
-True relapse/recurrence
P. vivax, P. ovale
-Reinvasion of RBCs by liver merozoites (from hypnozoites), after complete clearing of the blood stream by therapy or immunity
Species specific clinical features:
-Infection of Young RBCs
- P. vivax
- P. ovale
Species specific clinical features:
-Infection of Old RBCs
-P. malariae
Species specific clinical features:
-Infection of ALL RBCs
-P. falciparum
Effect of inherited Red Cell Anomalies:
-Hemoglobin S
P. falciparum protection
Effect of inherited Red Cell Anomalies:
-General protection (4)
- Thalassemia
- HbC
- HbE
- Hereditary persistence of HbF
Effect of inherited Red Cell Anomalies:
-Duffy negative blood type
P. vivax protection
Effect of inherited Red Cell Anomalies:
-G6PD deficiency
Protective against all species
Effect of inherited Red Cell Anomalies:
-Hereditary ovalocytosis
Cerebral malaria protection
Laboratory Diagnosis - Detection:
-stains (3)
- Wright stains
- Acridine orange*
- Rhodamine 123*
*Fluorescent stains
Laboratory Diagnosis - Detection:
-Screening
Thick blood films
Laboratory Diagnosis - Detection:
-Species identification
Thin blood films
When is the ideal time to obtain blood specimen?
Preceding the next anticipated fever spike
Examination of at least ____ oil immersion Thick Film fields or ____ thin film fiels is required to achieve the reported sensitivity (5 parasites/uL).
- 100 oil immersion Thick Film fields
- 300 Thin Film fields
