SPOROZOA Flashcards
Phylum: Apicomplexa → Class: Sporozoa → Blood species: Plasmodium
A. Plasmodium species
▪ Pathogenic to man
A. Plasmodium species
▪ Causative agent of malaria
A. Plasmodium species
Principal vector Anopheles minismus var. flavirostris
A. Plasmodium species
➢ Obligate intracellular parasites of blood and tissues
A. Plasmodium species
➢ Alternation of generations (sexual and asexual development)
A. Plasmodium species
➢ Alternation of host:
A. Plasmodium species
Sexual cycle – female mosquito (Anopheles minimus flavirostris)
A. Plasmodium species
Asexual cycle – man
A. Plasmodium species
✓ sporozoites liberated into the bloodstream via bite of an infected female mosquito
A. Plasmodium species
✓ through blood transfusion
A. Plasmodium species
✓ vertical transmission
A. Plasmodium species
➢ Anemia (due to massive red cell destruction), splenomegaly, joint pain
A. Plasmodium species
➢ Recurrent/Intermittent chills and fever (synchronized rupture of red blood cells)
A. Plasmodium species
Every 36 hours:
Malignant Tertian Malaria (P. falciparum)
Every 48 hours:
Ovale Malaria (P. ovale)
Every 48 hours:
Benign Tertian Malaria (P. vivax)
Every 72 hours:
Quartan Malaria (P. malariae)
➢ Quotidian fever – is caused by the asynchronous release of merozoites in the circulation
is most widely distributed and most prevalent worldwide
✓ Plasmodium vivax infection
is most likely fatal
✓ Plasmodium falciparum infection
: red cells, organisms and pigment can block the brain vessels
Cerebral malaria
: sudden massive intravascular hemolysis resulting to hemoglobinuria
Blackwater fever
- Microscopic identification of the malarial parasites in thick and thin blood smears stained with Giemsa or Wright’s stain is still important in making the definitive diagnosis and remains the gold standard method.
A. Plasmodium species
- Collection of specimen must be prior to fever spike
A. Plasmodium species
- Bone marrow (through sternal puncture)
A. Plasmodium species
- Serological tests (to detect the presence of malarial antibodies)
A. Plasmodium species
- Malaria RDTs (Rapid Diagnostic Tests):
Plasmodium LDH
Immunochromatography
– produced by both sexual and asexual stages and can distinguish between P. falciparum and non-P. falciparum species
Plasmodium LDH
Plasmodium LDH o Examples:
- Diamed Optimal IT
– detects Plasmodium-specific antigens; these target antigens are called HRP II (Histidine-rich protein)
Immunochromatography
Immunochromatography o Examples:
- Paracheck Pf test
- ParaHIT f test
A. Pre-erythrocytic/Exo-erythrocytic schizogony
I. Asexual phase in man (SCHIZOGONY/MEROGONY)
B. Erythrocytic schizogony
I. Asexual phase in man (SCHIZOGONY/MEROGONY)
C. Gametogony
I. Asexual phase in man (SCHIZOGONY/MEROGONY)
- Begins with the inoculation of the infective sporozoites to man during a mosquito blood meal
A. Pre-erythrocytic/Exo-erythrocytic schizogony
- Within ½ hour, they are carried through blood circulation into the liver parenchymal cells where they undergo nuclear and cytoplasmic division and develop into pre/exo-erythrocytic schizonts
A. Pre-erythrocytic/Exo-erythrocytic schizogony
- Schizonts rupture producing exoerythrocytic merozoites that reinvade liver cells, while other invade the RBCs
A. Pre-erythrocytic/Exo-erythrocytic schizogony
- In the RBC, merozoite develops into trophozoite
A. Pre-erythrocytic/Exo-erythrocytic schizogony
- In P. vivax and P. ovale, sporozoites develop into hypnozoites which remain dormant for years in the hepatocytes. At a predetermined time, the hypnozoites begin to grow and undergo exoerythrocytic schizogony releasing merozoites that invade RBCs causing a recurrence of the malaria attack
A. Pre-erythrocytic/Exo-erythrocytic schizogony
- The trophozoite further matures into schizont, then divide into erythrocytic merozoites
B. Erythrocytic schizogony
- RBC ruptures releasing merozoites into the bloodstream
B. Erythrocytic schizogony
- After 2 – 3 eryhtrocytic generations, Gametocytogenesis begins
C. Gametogony
- Some of the merozoites do not form schizont, but rather micro- and macrogametocytes which are infective to the mosquito
C. Gametogony
- The male and female gametocytes sucked in by the mosquito undergo maturation and differentiate into micro- and macrogametes
II. Sexual phase in mosquito (SPOROGONY)
- The microgamete exflagellates and fertilizes the macrogamete producing a zygote as a result of fertilization
II. Sexual phase in mosquito (SPOROGONY)
- Ookinete penetrates the stomach wall and forms an oocyst
II. Sexual phase in mosquito (SPOROGONY)
- Within the oocyst, numerous sporozoites are formed
II. Sexual phase in mosquito (SPOROGONY)
- Oocysts grows and ruptures releasing sporozoites
II. Sexual phase in mosquito (SPOROGONY)
- Sporozoites migrate through tissues to the salivary glands
II. Sexual phase in mosquito (SPOROGONY)
➢ Small ring forms (1/6 diameter red cell), applique forms, double nuclear dots
a. Plasmodium falciparum
➢ Organisms invades all ages of red blood cells (most severe)
a. Plasmodium falciparum
➢ Crescent/banana-shaped gametocytes
a. Plasmodium falciparum
➢ Single large compact ring or band forms
b. Plasmodium malariae
➢ Invades old RBCs
b. Plasmodium malariae
➢ Schizont with merozoites arranges around central pigment (resembles fruit pie)
b. Plasmodium malariae
➢ Ovoid gametocytes
b. Plasmodium malariae
➢ Single compact ring
c. Plasmodium ovale
➢ Large pale red cells with Schuffner’s dots which may be oval and fimbriated
c. Plasmodium ovale
➢ Single large ring succeeded by amoeboid form in pale large red cell
d. Plasmodium vivax
➢ Schuffner’s dot (condensed hemoglobin) in red cells
d. Plasmodium vivax
➢ Only reticulocytes are invaded
d. Plasmodium vivax
➢ Round gametocyte
d. Plasmodium vivax
Malignant malaria
a. Plasmodium falciparum
Quartan malaria
b. Plasmodium malariae
Ovale malaria
c. Plasmodium ovale
Tertian malaria
d. Plasmodium vivax
36- 48 hours
a. Plasmodium falciparum
72 hours
b. Plasmodium malariae
48 hours
c. Plasmodium ovale
d. Plasmodium vivax
Not enlarged
a. Plasmodium falciparum
b. Plasmodium malariae
Sometimes enlarged; frequently oval with ragged margins
c. Plasmodium ovale
Enlarged
d. Plasmodium vivax
Normal; multiply infected red blood cells are common
a. Plasmodium falciparum
Normal
b. Plasmodium malariae
Enlarged; approximately 20% or more of infected RBCs are oval and/or fimbriated (border has irregular projections)
c. Plasmodium ovale
Enrlaged; maximum size may be 1 – 2 times normal RBC diameter
d. Plasmodium vivax
6 – 32 (average is 20 – 24)
6 – 12 (average is 8); “rosette” schizonts
6 – 14; average is 8
12 – 24; average is 16
- (Maurer’s dots occasionally seen)
a. Plasmodium falciparum