[Elizabeth_Zeibig]_Clinical_Parasitology__A_Practi(z-lib.org)

CHAPTER 10 The Cestodes
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Lateral branches
(15-30 per side)
larva emerges in the small intestine, in which
maturation into an adult worm occurs. The
resulting adult multiplies, producing numerous
eggs, some of which may be passed into the feces.
These eggs are then consumed by the proper
animal species (cow or pig) in which the oncosphere
hatches. The oncosphere then migrates
via the blood to the animal tissue and converts
into the infective cysticercus larval stage. A new
cycle is initiated on human ingestion of the
infected animal meat.
Epidemiology
Average size: 17.5 by 5.5 mm
FIGURE 10-5 Taenia saginata proglottid.
Life Cycle Notes
Lateral branches
(7-15 per side)
FIGURE 10-6 Taenia solium proglottid.
Infection with Taenia spp. occurs following the
ingestion of raw or undercooked beef (T. saginata)
or pork (T. solium) contaminated with a
cysticercus larva, a type of larva that consists of
a scolex surrounded by a bladder-like, thinwalled
cyst that is filled with fluid. Scolex attachment
to the intestinal mucosa occurs after the
The distribution of T. saginata and T. solium
directly correlates with areas of the world in
which the inhabitants do not practice sanitary
conditions and beef or pork is eaten on a routine
basis. T. saginata is found primarily in these
types of cosmopolitan areas, whereas T. solium
is found worldwide. As noted, both organisms
require an intermediate host, a cow or pig,
depending on the species.
Clinical Symptoms
Asymptomatic. Most people who become
infected with Taenia spp. typically remain
asymptomatic.
Taeniasis: Beef or Pork Tapeworm Infection.
Nondescript symptoms, such as diarrhea, abdominal
pain, change in appetite, and slight weight
loss, may be experienced by Taenia-infected
patients. In addition, symptoms including dizziness,
vomiting, and nausea may also develop.
Laboratory tests often reveal the presence
of a moderate eosinophilia. The prognosis is
usually good.
Treatment
The most important and, in some cases, difficult
aspect of treatment of Taenia infections is
total eradication of the scolex. Fortunately, praziquantel
has proven effective against the entire
adult worm; however, it is not used when
there is ocular or central nervous system