15 Plasmodium and Malaria Flashcards
Factors affecting malaria
Temperature Altitude Humidity Rainfall Seasons
Causative agent of malaria
Plasmodium
Plasmodium is transmitted through the bite of what genus of mosquito
Anopheles
Most important parasitic infection
Most virulent
Responsible for malignant tertian fever
P. falciparum
Numerous smaller rings
Crescent-shaped gametocytes
Maurer’s clefts
P. falciparum
Irregular blotches developed by infected erythrocyte
Maurer’s clefts
Schizonts of P. falciparum contain how many merozoites
8-24
Responsible for benign tertian fever
P. vivax (along with P. ovale)
Enlarged erythrocyte
Schuffner’s dots
Amoeboid-shaped trophozoite
P. vivax
Peculiar stippling pattern observed from an enlarged red cell as a trophozoite grows inside it
Schuffner’s dots
Schizonts of P. vivax contain how many merozoites
12-24
Not endemic in the Philippines unless imported
Also involved in benign tertian fever
P. ovale
Trophoizotes are compact
Also contain Schuffner’s dots
P. ovale
Schizonts of P. ovale contain how many merozoites
6-14
Compact parasite
Merozoites form rosette pattern
P. malariae
P. malariae schizonts contain how many merozoites
6-12
Mostly known to infect Simian malaria
Considered zoonotic, infect humans
P. knowlesi
P. knowlesi forms what kind of stippling when observed under microscope
Sinton and Mulligan’s
Clinical presentation of P. knowlesi infection
Severe anemia
Thrombocytopenia
Acute respiratory distress syndrome
Definitive host of Plasmodium
Found in rural areas with clean, stagnant or running water
Anopheles
Intermediate host of Plasmodium
Man
Human liver stage
Schizonts and merozoites
Exo-erythrogenic schizogony
Ring-stage trophozoites
Schizonts
Merozoites
Erythocytic schizogony
Infective stage of Plasmodium
End product of the sporogonic cycle
Sporozoites
The primary site of plasmodium infection
Liver
Mature sporozoites in the liver
Schizonts
Individual small dots within the schizont
Daughter cells from the schizonts
Produced via asexual reproduction
Merozoites
Manifest with liver symptoms: jaundice and abdominal pain in the right upper quadrant/epigastric area
Exo-erythrocytic schizogony
Human blood stage
Daughter merozoites infect the RBCs
Erythrocytic schizogony
Stages of erythrocytic schizogony
Ring stage trophozoite
Schizonts
Merozoites
Early/young stage of trophozoite
Has a red chromatin dot and small amount of blue cytoplasm when stained with Giemsa or Wright’s stain
Ring stage trophozoite
Trophozoites dividide within the RBC
Contain multiple merozoites
Schizonts
Form the zygote via sexual reproduction
Macrogametocyte and microgametocyte
Mosquito phase
Sporogonic cycle
Stages of sporogonic cycle
Zygote Ookinetes Oocysts Sporocysts Sporozoites
Produces antigenic Pf proteins on the surface of RBCs, which serve as an escape mechanism from destruction by the spleen
P. falciparum
Most common and most well-documented complication of P. falciparum infection
Cerebral malaria
Renewal of parasitemia and/or clinical features arising from persistent unpredictable asexual parasitemia in the absence of exo-erythrocytic cycle
Only applicable for P. falciparum, P. malaria and P. knowlesi
Recrudescence
Dormant stage found in liver
Hypnozoites
Which Plasmodium species have hyponozoites in their life cycle
P. vivax and P. ovale
Results from the reactivation of hypnozoite forms of the parasite in the liver
Malaria relapse
Affects RBCs of all ages
P. falciparum
Affect young erythrocytes
P. vivax
P. ovale
Affect old or mature RBCs
P. malariae
P. knowlesi
Incubation period of P. falciparum
9-14 days
Incubation period of P. vivax/ovale
12-18 days
Incubation period of P. malariae
18-40 days
Incubation period of P. knowlesi
11-12 days
Cold stage
Midday
15 mins-1 hour
RBCs simultaneously burst out because of infection, releasing cytokines due to anemia
Chills
Hot stage, high grade fever, lasts up to 6 hours
High grade fever would be >39 deg C
Due to recruitment of tumor necrosis factor and interleukins
Length of phase depends on the species of malaria
Fever
Peaks every 48 hours
P. vivax and P. ovale
Benign tertian fever pattern
Fever peaks every 72 hours
P. malariae
Quartan fever pattern
Fever peaks in a range (24-48 hours) and is not exactly predictable
P. falciparum
Malignant tertian fever pattern
Fever peaks at about the same time every day (24 hours)
Quotidian fever pattern
Sweating stage with gradual resolution of fever
Merozoites infect uninfected RBCs
Reset of thermoregulatory system
Profuse sweating
Death of RBC leads to ____ state due to less oxygen delivery
Acidic
Converts lactic acid into pyruvate
Plasmodium lactate dehydrogenase
Sever malaria clinical manifestations
Cerebral malaria Severe anemia Renal failure Pulmonary edema/ARDS Hypoglycemia
Caused by widespread sequestration of infected erythrocytes in the cerebral microvasculature
Cerebral malaria
Most patients with particularly complicated malaria present with _____
Hypoglycemia
Diagnostic tools for Plasmodium
Antigen/enzyme determination Blood thick and thin smears Polymerase chain reaction Antibody detection Drug resistance
Dip stick or casette formation
Determines if the sample is P. falciparum or P. vivax
Antigen/enzyme determination
Antigens being tested in rapid diagnostic test
Histidine-rich protein II (HRP-2)
Plasmodium lactate dehydrogenase (pLDH)
Only for epidemiology studes
Antibody detection
In vitro tests
Molecular characterization
Drug resistance tests
Gold standard for diagnosis
Used for confirmation
Giemsa-stained
Blood thick and thin smears
When do you usually conduct blood smears to catch the rupture of the RBCs and the fever spike?
Every 6-12 hours for 48-72 hours
Greater sensitvity for screening of the presence of malarial infection
Thick smear
For species identification
For parasite density quantification
For visualizing schizonts/gametes
Thin smear
Characteristic of a P. falciparum gametocyte
Banana-shaped/elongated
unlike others that have circular shape
Stippling differentiation;
Maurer’s cleft
P. falciparum
Stippling differentiation James dots
P. ovale
Stippling differentiation Schuffner’s dots
P. vivax
Stippling differentiation:
Ziemann’s dots
P. malariae
Used as backup or confirmation of microscopy
Used to differentiate P. malariae from P. knowlesi
PCR
First-line drug
Schizonticidal
Artemeter/Lumefantrine
Acts on exo-erythrocytic stages
14-day treatment against P. vivax to kill hypnozoites and gametocytes
Primaquine
Used to be the primary drug for treatment of malaria
No longer used due to widespread resistance
Chloroquine
First-line treatment of unconfirmed malaria
AL
First-line treatment of P. falciparum
AL + PQ
Treatment failure of P. falciparum
QN (chloroquine, amodiaquine, quinines) + T (trimethroprim-sulfamethoxazole)
Treatment of severe malaria
QN + T
Treatment of P. vivax
CQ + PQ
Effective for both chemoprophylaxis and treatment of P. falciparum and P. vivax
Atovaquone
Proguanil
Other chemoprophylactic drugs
Chloroquine
Doxycycline
Mefloquine
Primaquine