dog tapeworm) mainly infects dogs and cats, but is occasionally found in
are passed intact in the feces or emerge from the perianal region of the
Subsequently they release typical egg packets
On rare occasions, proglottids rupture and egg packets are seen in stool
samples. Following ingestion of an egg by the intermediate host (larval
stages of the dog or cat flea Ctenocephalides spp.), an
oncosphere is released into the flea's intestine. The oncosphere
penetrates the intestinal wall, invades the insect's hemocoel (body
cavity), and develops into a cysticercoid larva
The larva develops into an adult, and the adult flea harbours the
The vertebrate host becomes infected by ingesting the adult flea
containing the cysticercoid
The dog is the principal definitive host for Dipylidium caninum.
Other potential hosts include cats, foxes, and humans (mostly children)
Humans acquire infection by ingesting the cysticercoid contaminated
flea. This can be promulgated by close contact between children and
their infected pets. In the small intestine of the vertebrate host the
cysticercoid develops into the adult tapeworm which reaches maturity
about 1 month after infection
The adult tapeworms (measuring up to 60 cm in length and 3 mm in width)
reside in the small intestine of the host, where they each attach by
their scolex. They produce proglottids (or segments) which have two
genital pores (hence the name "double-pored" tapeworm). The proglottids
mature, become gravid, detach from the tapeworm, and migrate to the anus
or are passed in the stool
infections have been reported in Europe, the Philippines, China, Japan,
Argentina, and the United States.
with Dipylidium caninum are asymptomatic. Pets may exhibit
behavior to relieve anal pruritis (such as scraping anal region across
grass or carpeting). Mild gastrointestinal disturbances may occur. The
most striking feature in animals and children consists of the passage of
proglottids. These can be found in the perianal region, in the feces,
on diapers, and occasionally on floor covering and furniture. The
proglottids are motile when freshly passed and may be mistaken for
maggots or fly larvae.
The diagnosis is
made by demonstrating the typical proglottids or egg packets in the
stool or the environment.
comparison with other intestinal parasites
Treatment for both
animals and humans is simple and very effective. Praziquantel is given
either orally or by injection (pets only). The medication causes the
tapeworm to dissolve within the intestines. Since the worm is usually
digested before it passes, it may not be visible in the dog's stool.
These drugs are generally well tolerated.