Chapter 6: Select Sporozoa: Plasmodium and Babesia Flashcards
(42 cards)
It refers to disease processes resulting from infections of parasites belonging to the phylum Apicomplexa.
Malaria and Babesiosis
Both genera of parasites belong to the class of parasites that have no obvious structures for the purpose of motility, known as?
Sporozoa
The space inside the ring is known as?
Vacuole
Quick Quiz 6-1
The infective stage of Plasmodium is (are)
A. Merozoites
B. Oocyst
C. Sporozoites
D. Gametocytes
C. Sporozoites
What are the specimens of choice for the laboratory diagnosis of malaria?
Giemsa-stained peripheral blood
The greatest number of parasites is present in the blood in between characteristic bouts of fever and chills resulting from the release of merozoites and toxic waste products from infected RBCs, known as
Paroxysms
The common associated disease and condition
names:
- Benign tertian malaria
- Vivax malaria
Relative age of infected RBCs:
- Only young and immature cells
Appearance of infected RBCs:
- Enlarged, distorted
Ring forms:
- Delicate cytoplasmic ring measuring one-third of RBC diameter
- Accolé forms possible
Developing trophozoite:
- Irregular ameboid appearance
- Ring remnants common
- Brown pigment becomes
Immature schizont:
- Multiple chromatin bodies
- Often contains clumps of brown pigment
Mature schizont:
- 12 to 24 merozoites
- Brown pigment may be present
Microgametocyte:
- Large pink to purple chromatin mass surrounded by colorless to pale halo
- Brown pigment common
Macrogametocyte:
- Round to oval cytoplasm
- Eccentric chromatin mass
- Light-brown pigment
Plasmodium vivax
The parasite may first be visible as a crescent-shaped mass at the outer edge of the red blood cell, a location known as
Accolé or Appliqué.
A remnant of the parasite feeding on RBC hemoglobin is visible as a brown pigment.
Hemozoin
In laboratory diagnosis, all morphologic forms of P. vivax may be seen on?
Thick and thin peripheral blood films
Note:
Although the best time to observe numerous infected RBCs is halfway between paroxysms
Treatment for P. vivax.
- quinine
- quinidine
- chloroquine
- amodiaquine
- primaquine
- pyrimethamine
- sulfadoxine
- dapsone
- mefloquine
- tetracycline
- doxycycline
- halofantrine
- atovaquone
- proguanil
- ginghaosu
- artemisinin
- artemether
- artesunate
- pyronaridine
- Fenozan B07
- trioxanes
- nonane
- endoperoxides
- azithromycin
- WRZ38605
The morphologic forms of P. vivax, with the exception of early ring forms that are less than 8 to 10 hours post-infection, may contain tiny granules in the cytoplasm is known as?
Schüffner’s dots
Quick Quiz 6-4
Which morphologic characteristic may help in distinguishing P. vivax from P. falciparum?
A. Hemozoin
B. Schüffner’s dots
C. 72-hour paroxysm
D. None of the above
B. Schüffner’s dots
Quick Quiz 6-5
P. vivax characteristically invades:
A. Immature RBCs
B. Senescent RBCs
C. All RBCs
D. Lymphocytes
A. Immature RBCs
Quick Quiz 6-6
The incubation period for P. vivax is generally:
A. 6 to 8 days
B. 7 to 10 days
C. 12 to 24 days
D. 10 to 17 days
D. 10 to 17 days
The common associated disease and condition
names:
- Benign tertian malaria
- Ovale malaria
Relative age of infected RBCs:
- Only young and immature cells
Appearance of infected RBCs:
- Oval and enlarged, distorted with ragged cell walls
Ring form:
- Resembles that of P. vivax
- Ring larger in size than P. vivax
Developing trophozoite:
- Ring appearance usually maintained until late in
development
Immature schizont:
- Progressive dividing chromatin surrounded by cytoplasmic material—often maintains circular shape early in development
Mature schizont:
- Parasites occupy 75% of RBCs
- Rosette arrangement of merozoites (average of eight merozoites typically present)
Microgametocyte & Macrogametocyte
- Similar to P. vivax, only smaller in size
Plasmodium ovale
In laboratory diagnosis, all developmental stages of P. ovale may be seen on?
Blood film preparations
These are usually difficult to distinguish because of their remarkable similarities for P. vivax and P. ovale.
Microgametocyte & Macrogametocyte
Quick Quiz 6-7
Which morphologic form would be the best choice
for distinguishing between P. vivax and P. ovale?
A. Mature schizont
B. Ring form
C. Early trophozoite
D. Immature schizont
A. Mature schizont
Quick Quiz 6-9
Which of the following is considered an antimalarial medication?
A. Amoxicillin
B. Erythromycin
C. Chloroquine
D. Dicyclomine
C. Chloroquine
The common associated disease and condition
names:
- Quartan malaria
- Malarial malaria
Relative age of infected RBCs:
- Only mature cells
Appearance of infected RBCs:
- Normal size, no distortion
Ring form:
- Smaller than P. vivax
- Occupies one sixth of the RBC
- Heavy chromatin dot
- Vacuole may appear filled in
- Pigment characteristically forms early
Developing trophozoite:
- Roundish, oval, band, or bar shape
- Cytoplasm contains coarse dark brown pigment
- Vacuoles absent in mature stages
Immature schizont:
- Similar to that of P. vivax, only smaller; may contain large and dark peripheral or central granules
Mature schizont:
- Typically contains 6 to 12 merozoites arranged in rosettes or irregular clusters
Microgametocyte & Macrogametocyte:
- Similar to P. vivax, only smaller in size; pigment usually darker and coarser
- Older forms assume an oval shape
Plasmodium malariae
The cytoplasm of heavily stained P. malariae may contain fine dustlike dots known as?
Ziemann’s dots
In laboratory diagnosis, this stage is not commonly seen in P. malariae.
Ring form
The most frequently encountered growth stages of
malariae seen are?
- Developing trophozoite
- Immature
- Mature schizonts
