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CANINE TAPE WORMS
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They are found in the gut of the
dog. Their hosts are fleas, sheep, rabbits and raw meat that is infected.
These worms travel down the digestive tract and itch the anus. During treatments
they expel in stools.
THE PET HEALTH
LIBRARY
Tapeworms
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.
As Rover
sleeps, tapeworm segments are passed
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.
Tapeworm
segments and flea dirt are found together in Rover’s dog bed.
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.
Tapeworm
segment breaks, releasing eggs. Eggs are eaten by grazing flea larva. Flea
larva pupate.
As the larval flea progresses in its development, the tapeworm inside
it is also
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Rover licks himself and swallows fleas
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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.
For more information on fleas and flea control, click here to go to a
special area prepared by the Iowa State Veterinary College: http://www.vetmed.iastate.edu/services/vth/clinical/derm/flea.html
Why is it Called a Tapeworm?
This creature gets its name because its segments and body are very flat
(like a piece of tape).
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.
Where do They Come From?
There is no other way for a pet to get Dipylidium caninum except from
fleas.
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.
There is another type of tapeworm that may be confused with Dipylidium
caninum and that is the Taenia genus of tapeworms. This is a different
type of tapeworm with a different appearing segment and a different mechanism
of infection.
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.
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.
How do We Get Rid of Them?
Tapeworms are killed by different medications (one is called , brand
name 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.
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 3 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.
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.
Why Might a Pet Continue to Get Tapeworm Infections?
While many people would like to blame the medication as 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.
Copyright
2001 - 2007 by the Veterinary Information Network, Inc. All rights reserved.
This work was originally published by Veterinary Information Network,
Inc. (VIN)
and is republished with VIN's permission.
The above information is simply informational.
It's intent is not to replace the advice of a veterinarian nor to assist
you in making a diagnosis of your pet. Please consult with your own veterinarian
for confirmation of any diagnosis. Your pets life may depend on it.
