Page 700 - Clinical Hematology_ Theory _ Procedures ( PDFDrive )

684 PART 8 ■ Fundamentals of Hematological Analysis

SPECIAL HEMATOLOGY PROCEDURES (continued)

Early "ring" forms Trophozoite Schizont Gametocytes

m Not usually Not usually
u
r seen in seen in
a
p
i peripheral peripheral
c
l blood blood
a
f
P.

e
l
a
v
o
P.

&

x
a
v
i
v
P.

e
a
i
r
a
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FIGURE 32.9 Malarial parasites in bloo cells. T is schematic rawing illustrates the most prominent morpho-

logical eatures that istinguish human malarial species in bloo smears. T e nuclear chromati bo ies o all o the

malarial parasites are sha e in ark blue-gray in this iagram but actually appear re in Giemsa-staine prepara-
tions. Plasmodium falciparum usually appears as small, f ne, ring orms, sometimes more than one per re bloo cell.

More-mature orms o the species are not usually seen in the peripheral bloo . T e gametocyte is characteristically

banana shape . P. vivax an P. ovale are istinguishe by etails not illustrate here. In ecte cells an ring orms are
larger than those o P. falciparum. At the trophozoite stage, re Schu ner ots are seen. T e schizont contains more

than a ozen merozoites be ore it ruptures. P. malariae in ects smaller, senescent cells. Schu ner ots are not present.

At the schizont stage, 8 to 12 merozoites are arrange peripherally aroun the central malarial pigment. (Reprinte

rom Engleberg NC, Dermo y , DiRita V. Schaecter’s Mechanisms of Microbial Disease, 4th e , Baltimore, MD:

Lippincott Williams & Wilkins, 2007, with permission.)

TABLE 32.2 Morphological Comparison of Plasm odium sp.

RBC Appearance Parasitic Appearance

Species Size Inclusions Cytoplasm Merozoites

P. vivax Enlarged Schuffner dots Blue discs with red nucleus 12–24

Accole forms

Signet ring forms

P. falciparum Normal Maurer dots Minute rings 6–32

Two chromatic dots

Accole forms

Gametes: crescent shaped

P. malariae Normal Ziemann dots One ring with one dot 6–12

P. ovale Enlarged Schuffner dots One ring form 6–14