TAPEWORM INFECTION
What are tapeworms?
The most common tapeworm of dogs (and cats) is called Dipylidium caninum.
This parasite attaches to the small intestinal wall by hook-like mouthparts.
Adult tapeworms may reach 20 cm. (8 inches ) in length. The adult worm is actually
made up of many small segments about 3 mm (1/8 inch ) long. As the tail end
of the worm matures, the terminal segments break off and pass into the feces.
Occasionally, the mobile segments can be seen crawling near the anus or on the
surface of a fresh bowel movement. These segments look like grains of rice and
contain tapeworm eggs; the eggs are released into the environment when the segment
dries. The dried segments are small (about 2 mm (or 1/16") hard and golden in
color. These dried segments can sometimes be seen stuck to the hair around the
dog's anus.
How did my dog get tapeworms?
First, tapeworm eggs must be swallowed by flea larvae (an immature stage of
the flea). Contact between flea larvae and tapeworm eggs is thought to occur
most frequently in contaminated bedding or carpet. The life cycle of the tapeworm
cannot be completed unless the flea swallows tapeworm larvae.
Next, the dog chews or licks its skin as a flea bites; the flea is then swallowed.
As the flea is digested within the dog's intestine, the tapeworm hatches and
anchors itself to the intestinal lining.
What kind of problems do tapeworms cause for the dog?
Tapeworms are not highly pathogenic (harmful) to your dog. They may cause
debilitation and weight loss when they occur in large numbers. Sometimes, the
dog will scoot or drag its anus across the ground or carpet because the segments
are irritating to the skin in this area. The adult worm is generally not seen,
but the white segments which break away from the tapeworm and pass outside the
body are usually noticed.
Occasionally, a tapeworm will release its attachment in the intestines and
move into the stomach. This irritates the stomach, causing the dog to vomit
the worm. When this happens, a worm several inches in length will be seen.
How is tapeworm infection diagnosed?
Tapeworm infection is usually diagnosed when the white, mobile segments are
seen crawling on your dog or in the feces. Tapeworms are not usually detected
by the routine fecal examination performed by your veterinary surgeon, thus
they will tend to depend on owner's description of the rice grain like segments
having been seen.
How is tapeworm infestation treated?
Treatment is simple and, fortunately, very effective. A drug which kills tapeworms
is given, either orally or by injection. It causes the tapeworm to dissolve
within the intestines. Since the worm is usually digested before it passes,
it is not visible in your dog's feces. These drugs should not cause vomiting,
diarrhea, or any other adverse side-effects. The same preparation is often effective
against Roundworm as well.
Control of fleas is very important in the management and prevention of tapeworm
infection. Flea control involves treatment of your dog, the indoor environment
and any outdoor environment where the dog habitually resides. If the dog lives
in a flea-infested environment, reinfection with tapeworms may occur in as little
as two weeks. Because the medication which treats tapeworm infection is so effective,
return of the tapeworms is almost always due to reinfection from the environment
and not failure of the product.
How do I tell tapeworms from pinworms?
Tapeworms and pinworms look very similar. However, contrary to popular belief,
pinworms do not infect dogs or cats. Any worm segments seen associated with
dogs are due to tapeworms. Children who get pinworms do not get them from dogs
or cats.
Are canine tapeworms infectious to people?
Yes, although infection is not common or likely. A flea must be ingested for
humans to become infected with the most common tapeworm of dogs. Most reported
cases have involved children. The most effective way to prevent human infection
is through aggressive, thorough flea control. The risk of infection with this
tapeworm in humans is quite small but does exist.
One less common group of tapeworms, called Echinococcus, is of particular
concern as a threat to human health. These tapeworms cause very serious disease
when humans become infected. This parasite is harder to diagnose than Dipylidium
because the segments are small and not readily seen. Sheep as well as humans
are the final hosts and dogs eating sheep carcasses can pass the eggs in their
feces. and thus, with lack of hygiene, humans can become affected from the eggs
passed in dog feces. Dogs and cats may also become infected if they eat rodents
carrying the parasite. Rodent control and good hygiene are important in preventing
the spread of this disease to humans. As with the more common tapeworm, infection
with Echinococcus is infrequent but possible.
What can be done to control tapeworm infection in dogs and to prevent human
infection?
1. Effective flea control is important.
2. Prompt deworming should be given when parasites are detected; periodic
deworming may be appropriate for pets at high risk for reinfection.
3. All pet feces. should be disposed of promptly, especially in yards,
playgrounds, and public parks.
4. Strict hygiene is important, especially for children. Do not allow
children to play in potentially contaminated environments.
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