[Elizabeth_Zeibig]_Clinical_Parasitology__A_Practi(z-lib.org)

CHAPTER 10 The Cestodes
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ingestion of an intermediate host’s dog or cat
fleas. These fleas may be transmitted by the lick
of an infected dog or cat or by hand-to-mouth
contamination. Ingestion of contaminated food
has also been known to initiate infection. Intestinal
infection occurs following human ingestion
of the larval stage. The resulting adult worm selffertilizes.
Characteristic egg packets and gravid
proglottids may be subsequently passed in the
stool. To continue the cycle, the eggs must be
ingested by a dog or cat flea, in which larval
development occurs. The swallowing of an
infected flea initiates a new cycle. It is important
to note that humans take the place of the dog or
cat in the life cycle when they become infected.
Epidemiology
The incidence of D. caninum infection is worldwide.
Children appear to be the most at risk for
infection transmission.
Clinical Symptoms
Asymptomatic. Most infected persons experience
no symptoms because of a light worm
burden (infection).
Dipylidiasis: Dog or Cat Tapeworm Disease.
Patients with a heavy worm burden may develop
appetite loss, diarrhea, abdominal discomfort,
and indigestion. They may also experience anal
pruritus caused by gravid proglottids migrating
out of the anus.
Treatment
The treatment of choice for infections with D.
caninum is praziquantel. Niclosamide (if available)
and paromomycin have proven to be effective
alternative treatments.
Prevention and Control
There are three primary prevention and control
measures that if strictly instituted, would most
likely eradicate human D. caninum infection.
First, dogs and cats should be examined by a
veterinarian on a regular basis. Routine procedures
should include deworming infected animals
(the process of worm removal via medication)
and periodic administration of prophylactic antihelminth
medications. Second, dogs and cats
should be treated and protected against flea
infestation regularly. Finally, children should be
taught not to let dogs or cats lick them in or near
their mouths.
Quick Quiz! 10-13
A unique characteristic of Dipylidium caninum is
which of the following? (Objective 10-10A)
A. Lack of suckers on the scolex
B. Formation of egg packets
C. Proglottid resemblance to Taenia solium
D. Alternation of female and male proglottids
Quick Quiz! 10-14
A 2-year-old girl and her pet dog were diagnosed
with D. caninum infection. This infection was acquired
by which of the following? (Objective 10-5)
A. Ingestion of the parasite’s egg
B. Penetration of soil larva
C. Ingestion of a flea
D. Consumption of poorly cooked beef
Quick Quiz! 10-15
Prevention and control measures to prevent D.
caninum infection include all except which of the
following? (Objective 10-7B)
A. Treat dog and cat pets to prevent fleas.
B. Warn children against dog and cat licks.
C. Deworm dog and cat pets, as needed.
D. Neuter dog and cat pets.
Diphyllobothrium latum
(dye-fil”o-both-ree-um/lay’tum)
Common name: Broad fish tapeworm.
Common associated disease and condition
names: Diphyllobothriasis, fish tapeworm infection,
broad fish tapeworm infection.