 |
| A |
A:
The stages of P. falciparum. 1:
Normal red cell; Figs. 2-18: Trophozoites (among these, Figs.
2-10
correspond to ring-stage trophozoites); Figs. 19-26: Schizonts (Fig.
26 is a ruptured schizont); Figs. 27, 28: Mature macrogametocytes
(female); Figs. 29, 30: Mature microgametocytes (male).
 |
A
|
A: Thick smear of P.
falciparum.
Ring-form
trophozoites (rings) of Plasmodium falciparum are often thin and delicate,
measuring on average 1/5 the diameter of the red blood cell. Rings may
possess one or two chromatin dots. They may be found on the periphery
of the RBC (accolé,
appliqué)
and multiply-infected RBCs are not uncommon. Ring forms may become
compact or pleomorphic depending on the quality of the blood or if there is
a delay in making smears. There is usually no enlargement of infected
RBCs.
 |
 |
| A | B |
A, B: Rings of P.
falciparum in a thick blood smear.
 |
 |
C
|
D
|
C, D: Rings of P. falciparum in
thick blood smears.
 |
 |
| E | F |
E, F: Rings of P. falciparum in
thick blood smears.
Ring-form
trophozoites (rings) of Plasmodium falciparum are often thin and delicate,
measuring on average 1/5 the diameter of the red blood cell. Rings may
possess one or two chromatin dots. They may be found on the periphery
of the RBC (accolé,
appliqué)
and multiply-infected RBCs are not uncommon. Ring forms may become
compact or pleomorphic depending on the quality of the blood or if there is
a delay in making smears. There is usually no enlargement of infected
RBCs.
 |
 |
| A | B |
A,
B: Rings of P. falciparum in a thin blood smear.
 |
 |
| C | D |
C,
D: Rings of P. falciparum in thin blood smears.
 |
 |
| E | F |
E: Rings
of P. falciparum in a thin blood smear.
F: Rings of P. falciparum in a thin blood smear. Image courtesy of the Arizona State Public Health Laboratory.
F: Rings of P. falciparum in a thin blood smear. Image courtesy of the Arizona State Public Health Laboratory.
Maurer's clefts can be seen in P. falciparum
infections containing older ring-form trophozoites and asexual stages.
Maurer's clefts resemble the Schüffner's dots seen in P. vivax and
P. ovale, but are usually larger and more coarse. Visualization of
these structures is dependent on the quality of the smear preparation and
the pH of the Giemsa stain. Like Schüffner's dots, Maurer's clefts
appear to play a role in the metabolic pathways of the infected RBCs.
 |
 |
| A | B |
A,
B: Ring-form trophozoites of P. falciparum in a thin
blood smear, exhibiting Maurer's clefts.
 |
 |
| C | D |
C,
D: Ring-form trophozoites of P. falciparum in a thin
blood smear, exhibiting Maurer's clefts.
 |
 |
| E | F |
E,
F: Ring-form trophozoites of P. falciparum in a thin
blood smear, exhibiting Maurer's clefts.
Developing trophozoites of P. falciparum tend to remain in ring form, but
may become thicker and more compact. The amount of pigment and chromatin may also
increase. Compact or amoeboid forms may be seen in smears where there
was a delay in processing the blood.
 |
 |
| A | B |
A:
Trophozoites of P. falciparum in a thick blood smear
B: Trophozoite of P. falciparum in a thin blood smear.
B: Trophozoite of P. falciparum in a thin blood smear.
 |
 |
| C | D |
C,
D: Trophozoites of P. falciparum in thin blood smears.
In Figure D, a gametocyte can also be seen in the upper half of
the image.
 |
 |
| E | F |
E,
F: Trophozoites of P. falciparum in thin blood smears
 |
A
|
A:
Gametocytes of P. falciparum. Figs.
27-28: Macrogametocytes (female); Figs. 29-30:
Microgametocytes (male).
Schizonts are rarely seen in peripheral blood of
Plasmodium falciparum infections, except in severe cases. When
seen, schizonts contain anywhere from 8-24 merozoites. A mature
schizont usually fills about 2/3 of the infected RBC.
 |
 |
| A | B |
A,
B: Schizonts of P. falciparum in a thin blood smear.
 |
| C |
C:
Schizont of P. falciparum in a thin blood smear.
Trophozoites are also seen in this image.
 |
| A |
A:
Schizonts of
P. falciparum. Figs. 19-25: Increasingly mature
schizonts; Fig. 26: Ruptured schizont.
Gametocytes of Plasmodium falciparum are crescent-
or sausage-shaped, and are usually about 1.5 times the diameter of an RBC in
length. The cytoplasm of the macrogametocytes (female) are usually a
darker, deeper blue; the cytoplasm of the microgametocytes (male) is usually
more pale. The red chromatin and pigment is more coarse and
concentrated in the macrogametocytes than the microgametocytes.
Sometimes in thin blood smears, the remnants of the host RBC can be seen;
this is often referred to as Laveran's bib.
 |
 |
| A | B |
A,
B: Gametocytes of P. falciparum in thick blood smears.
Note also the presence of many ring-form trophozoites.
 |
| C |
C:
Gametocytes of P. falciparum in a thick blood smear.
Gametocytes of Plasmodium falciparum are crescent-
or sausage-shaped, and are usually about 1.5 times the diameter of an RBC in
length. The cytoplasm of the macrogametocytes (female) are usually a
darker, deeper blue; the cytoplasm of the microgametocytes (male) is usually
more pale. The red chromatin and pigment is more coarse and
concentrated in the macrogametocytes than the microgametocytes.
Sometimes in thin blood smears, the remnants of the host RBC can be seen;
this is often referred to as Laveran's bib.
 |
 |
| A | B |
A:
Gametocyte of P. falciparum in a thin blood smear. Also
seen in this image are ring-form trophozoites and an RBC exhibiting
basophilic stippling (upper left).
B: Gametocyte of P. falciparum in a thin blood smear. Also seen in this image are ring-form trophozoites exhibiting Maurer's clefts.
B: Gametocyte of P. falciparum in a thin blood smear. Also seen in this image are ring-form trophozoites exhibiting Maurer's clefts.
 |
 |
| C | D |
C, D:
Gametocytes of P. falciparum in thin blood smears. In
these specimens, Laveran's bibs can be seen.
 |
 |
ليست هناك تعليقات:
إرسال تعليق