Biology of the Parasite (Dipylidium caninum)
The adult Dipylidium caninum lives in the small intestine of the dog or cat.
It is hooked onto the intestinal wall by a structure called a rostellum
which is sort of like a hat with hooks on it. The tapeworm also has six rows
of teeth to grab on with. Most people are confused about the size of a
tapeworm because they only see its segments which are small; the entire
tapeworm is usually 6 inches or more.
Once docked like a boat to the host intestinal wall, the tapeworm begins
to grow a long tail. (The tapeworm’s body is basically a head segment to
hold on with, a neck, and many tail segments). Each segment making up the
tail is like a separate independent body, with an independent digestive
system and reproductive tract. The tapeworm absorbs nutrients through its
skin as the food being digested by the host flows past it. Older segments
are pushed toward the tip of the tail as new segments are produced by the
neckpiece. By the time a segment has reached the end of the tail, only the
reproductive tract is left. When the segment drops off, it is basically just
a sac of tapeworm eggs.
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Tapeworm butt
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As Rover sleeps, tapeworm segments are
passed
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The sac is passed from the host’s rectum and out into the world, either
on the host’s stool or on the host’s rear end. The segment is the size of a
grain of rice and is able to move. Eventually the segment will dry and look
more like a sesame seed. The sac breaks and tapeworm eggs are released.
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Tapeworm dirt
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Tapeworm segments and flea dirt are
found together in Rover’s dog bed.
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Larval fleas are generally hatching in this vicinity and these larvae are
busy grazing on organic debris and flea dirt (the black specks of digested
blood shed by adult fleas to nourish their larvae). The flea larvae do not
pay close attention to what they eat and innocently consume tapeworm eggs.
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Tapeworm
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Tapeworm segment breaks, releasing eggs.
Eggs are eaten by grazing flea larva. Flea larva pupate.
Also segment can be eaten by mice or rabbits
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As the larval flea progresses in its development, the tapeworm inside it
is also progressing in development. By the time the flea is an adult, the
tapeworm is ready to infect a dog or cat. The flea goes about its usual
business, namely sucking its host’s blood, when to its horror, it is licked
away by the host and swallowed
Inside the host’s stomach, the flea’s body is digested away and the young
tapeworm is released. It finds a nice spot to attach and the life cycle
begins again. It takes 3 weeks from the time the flea is swallowed to the
time tapeworm segments appear on the pet’s rear end or stool.
FAQS
Why is it called
a “Tapeworm”
What do they look like?
Where do they come
from?
How do you know if
your pet has them? Why do they sometimes fail to show up in a fecal test?
Can people get them?
How do we get rid
of them?
Why do some
veterinarians recommend two treatments, and others only recommend one
treatment?
If one pet
has tapeworm segments, can it be assumed that they all do?
Why might a pet
continue to get tapeworm segments?
WHY IS IT CALLED A “TAPEWORM?”
This creature gets its name because its segments and body are very flat
(like a piece of tape).
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WHAT DO THEY LOOK LIKE?
The adult tapeworm inside the pet be a half a foot or more long. It is made
of small segments, each about the size of a grain of rice. The tapeworm’s
head hooks onto the dog’s intestine by tiny teeth and the worm absorbs
nutrients through its skin. Each segment contains a complete set of organs
but as new segments grow in at the neck area and older segments progress to
the tip of the tail, the organs disintegrate except for the reproductive
organs. When the segment drops off from the tail tip, it is only a sac of
eggs.
This segment is white and able to move when it is fresh and, at this
time, looks like a grain of white rice. As the segment dries, it looks more
like a sesame seed.
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WHERE DO THEY COME FROM?
Most tapeworms come from
fleas, but there are other species of tapeworm that come
from pets eating mice & rabbits.
Many people who had thought their pet could not possibly have fleas find
out about the infestation this way. The tapeworm segment breaks open
releasing its eggs. A larval flea consumes the egg along with the flea dirt
that it normally eats. As the larval flea matures, so does the baby
tapeworm. When a grooming dog or cat licks the flea and swallows it, the
dead flea is digested in the dog’s stomach releasing the baby tapeworm. The
tapeworm is passed to its new home in the dog or cat’s small intestine where
it attaches and lives its life.
This parasite does not harm the pet in any way as there are plenty of
nutrients passing by to serve both the host and its tapeworm (tapeworms
require very little nutrients.) Still, high performance dogs, who need every
Calorie working for them, may show a decrease in performance because of a
tapeworm infection.
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HOW DO YOU KNOW IF YOUR PET HAS THEM?
WHY DO THEY SOMETIMES FAIL TO SHOW UP IN A FECAL TEST?
Because the eggs are passed by the pet in packets (segments), they often do
not show up on the fecal exam. (The packet must break open for the eggs to
be seen.) Consider that the pet has tapeworms if segments are seen under its
tail, around its anus, or on its feces. Segments can be passed in small
groups connected to each other leading the owner to describe a worm that
sounds larger than a grain of rice. Tapeworm segments are also quite flat.
Some people will mistake maggots in the stool for tapeworms. Maggots are
not seen in freshly passed stool and are not flat.
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CAN PEOPLE GET THEM?
Theoretically, yes, people can get them but they must be infected the same
way dogs and cats are: by swallowing an infected flea.
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HOW DO WE GET RID OF THEM?
Tapeworms are killed by different medications (one is called “DRONCIT”
(brand name of “Praziquantel”
) which is administered by injection or tablet. The tapeworm is killed and
digested with the pet’s food. It is not passed in the stool later.
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WHY DO SOME VETERINARIANS RECOMMEND TWO TREATMENTS AND OTHERS ONLY
RECOMMEND ONE TREATMENT?
Only one treatment is needed to kill tapeworms present; however, many
clinics recommend a second injection in three weeks. The reason for the
second injection is this: If the owner finds out at the time of their office
visit that they need to control fleas to control tapeworms, they will need
at least a month or so to control the fleas.
After the first treatment is given, there is no reason why the pet cannot
immediately reinfect itself. It probably will reinfect itself at some
point. By seeing the animal in three weeks and giving another treatment
after the fleas are controlled, there is a good chance that the tapeworms
will not just be back three weeks later. It takes three weeks from the time
tapeworms are swallowed by the pet to the time segments can be seen by the
owner.
On the other hand, who knows when the pet will swallow another infected
flea? Our recommendation is that a single treatment be administered whenever
segments are seen.
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IF ONE PET HAS TAPEWORM SEGMENTS, CAN IT BE ASSUMED
THAT THEY ALL DO?
No, just because one pet in the household has swallowed an infected flea
does not mean they all have. Our recommendation is to deworm only the pets
who have obvious tapeworms.
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WHY MIGHT A PET CONTINUE TO GET TAPEWORM INFECTIONS?
While many people would like to blame the medication as having been
ineffective, the truth is that there must be an on-going flea population in
the pet’s environment. The key to eradicating tapeworms from the home is
flea control. Active, outdoor and "ranch" or roaming dogs
and hunting cats may continue to re-infest themselves even after routine de
worming.
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