[Elizabeth_Zeibig]_Clinical_Parasitology__A_Practi(z-lib.org)

CHAPTER 10 The Cestodes
243
Three pairs
of hooklets
Radial striations
on yellow-brown
embryophore
Hexacanth
Embryo
A
Size range: 28-40 m by 18-30 m
Average length: 33 m by 23 m
33 23 m
B
C
FIGURE 10-2 A, Taenia spp. egg. B, Taenia spp.unembryonated egg, 400×. C, Taenia spp. embryonated egg, 400×.
(B, C courtesy of Carolina Biological Supply, Burlington, NC.)
TABLE 10-1
Parameter
Taenia Species Egg: Typical
Characteristics at a Glance
Description
Size range 28-40 µm by 18-30 µm
Hooklets
Three pairs; hexacanth embryo
Other features Radial striations on yellowbrown
embryophore
three pairs of hooklets. The embryo is surrounded
by a yellow-brown shell present on select tapeworm
eggs known as an embryophore on which
distinct radial striations reside. These eggs may
be nonembryonated (see Fig. 10-2B) or embryonated
(see Fig. 10-2C).
Scolices. The typical Taenia spp. scolex measures
from 1 to 2 mm in diameter and is equipped
with four suckers (Figs. 10-3 and 10-4; Table
10-2). The primary difference between those of
T. saginata and T. solium is that the latter contains
a fleshy rostellum and double crown (row)
of well-defined hooks (Fig. 10-4), whereas the
former lacks these structures.
Proglottids. The average number of segments
(proglottids) of typical T. saginata and T. solium
adult worms is 1048 and 898, respectively
(Table 10-2). There are two primary differences
between the internal structures in the proglottids
of the two Taenia organisms, appearance and
number of uterine branches on each side of the