[Elizabeth_Zeibig]_Clinical_Parasitology__A_Practi(z-lib.org)

CHAPTER 11 The Trematodes
269
Operculum
Undeveloped
miracidium
A
Fasciolopsis size range: 128-140 m by 78-85 m
Fasciola size range: 128-150 m by 60-90 m
B
FIGURE 11-2 A, Fasciolopsis buski egg. B, Fasciolopsis buski, Fasciola hepatica egg. (B from Mahon CR, Lehman DC,
Manuselis G: Textbook of diagnostic microbiology, ed 4, St Louis, 2011, Saunders.)
Fasciolopsis buski
(fa-see’o-lop’sis/bus’kee)
Common name: Large intestinal fluke.
Common associated disease and condition
names: Fasciolopsiasis.
No shoulder
Fasciola hepatica
(fa-see’o-luh/he-pat’i-kuh)
Common name: Sheep liver fluke.
Common associated disease and condition
names: Fascioliasis, sheep liver rot.
Morphology
Eggs. Even though a size range has been
established for the eggs of Fasciolopsis buski as
well as for Fasciola hepatica, there is significant
overlapping of the numbers (Fig. 11-2; Table
11-1). The typical F. buski egg measures 128
to 140 µm by 78 to 85 µm, whereas that of
F. hepatica measures 128 to 150 µm by 60 to
90 µm. The eggs are identical in all other respects.
They consist of an oblong undeveloped miracidium
equipped with a distinct operculum. The
eggs of the two species are considered to be
indistinguishable.
Adults. The somewhat oblong, fleshy adult F.
buski (Fig. 11-3) averages 5 by 1.5 cm in size.
TABLE 11-1
Parameter
Size range
Shape
Egg contents
Other features
Average size: 5 cm by 1.5 cm
FIGURE 11-3 Fasciolopsis buski adult.
Fasciolopsis buski and
Fasciola hepatica Egg:
Typical Characteristics
at a Glance
Description
F. buski, 128-140 µm by 78-85 µm;
F. hepatica, 128-150 µm by
60-90 µm
Somewhat oblong
Undeveloped miracidium
Presence of a distinct operculum