Dogs and cats can become hosts to many intestinal parasites and a few
general statements apply to all parasitic infections:
1. All deworming medicines are poisonous to some extent and should only
be used as needed and under proper conditions.
2. At this time there is no one dewormer that can eliminate all species
of parasites. Consequently an accurate diagnosis is necessary to treat
your pet properly.
3. Diagnosis is usually made from a fresh stool sample (passed less than
12 hours) or, in the case of tapeworms, seeing the segments in the stool.
4. Most puppies and kittens are infected before birth and, for this reason,
will need deworming starting at 6 weeks of age. If hookworms are suspected,
stools should be checked starting as early as 2-3 weeks.
5. Occasionally, for a heavy parasitic infection, 3 or even 4 treatments
may be necessary to eliminate the parasite.
The following is a brief description of the common intestinal parasites
with their symptoms, diagnosis, treatment, prevention, and human transmission.
ROUNDWORMS - This is a common worm of puppies and kittens,
but can be seen in any age dog or cat. Diagnosis is made from a microscopic
examination of the feces or from a description of the worm if it is
seen in the stool or vomitus. Treatment is an oral medication given
at 2 week intervals. Symptoms will vary from none to marked vomiting
and diarrhea, and abdominal swelling. Transmission to adult dogs and
cats occurs by infected feces contaminating the yard. As a result, prevention
is accomplished by isolating your pet from infected feces of other animals.
For dogs, the heartworm preventatives also prevent roundworm infection.
Transmission to humans is rare; young children can develop "visceral
larval migrans" by eating dirt contaminated with feces.
HOOKWORMS - This is also a common worm of puppies and
kittens but is seen with equal frequency in adults. This parasite sucks
your pet's blood and can cause a severe anemia. Diagnosis is made from
a microscopic examination of your pet's stool. Treatment is either an
oral medication or an injection or both. This is repeated 2 weeks later.
Symptoms will vary from none to blood in the stool (dark tar-colored
stool) with diarrhea. Severe cases may need a transfusion and hospitalization.
Transmission to adults occurs by infected feces contaminating the grass
or soil. Prevention, therefore, requires that the pet be kept away from
contaminated areas. Two types of heartworm preventative can also prevent
hookworm infections in dogs. Transmission to humans is uncommon and
is usually shows up as skin lesions.
WHIPWORMS - This worm affects dogs only. Diagnosis is
also made from a microscopic exam of the feces. Eggs from this parasite
pass intermittently, however, so it may be necessary to check multiple
fecals before a diagnosis is made. Treatment is an oral medication given
at 3 to 6 week intervals depending on the severity of the infection.
Symptoms vary from none to a severe watery diarrhea, vomiting, and marked
weight loss. Some dogs require hospitalization for treatment of dehydration,
malnutrition, and infection. Prevention of this worm is now possible
with the heartworm preventatives Interceptor and Filaribits Plus. There
is no human transmission.
TAPEWORMS - This common worm affects both dogs and cats.
Transmission occurs when your dog or cat bites and "eats"
a flea. The intermediate form of the tapeworm is inside the flea's body
and it then attaches to the intestine and begins to grow "segments".
In about 3 weeks, these segments begin to pass in the stool. They are
approximately ¼ to ½ inch long, flat, and white. After
a short time in the air, they dry up to resemble a small yellow flat
seed. Diagnosis is made from seeing these segments on the stool or on
the pet's back end rather than a microscopic fecal exam. Treatment is
either by oral tablets or by an injection. The tapeworm infection kills
existing tapeworms but it does not prevent future infection. The only
prevention is strict flea control. There is no direct transmission from
dog or cat to a human.
GIARDIA - This parasite is not a worm. It is a very tiny
single-celled parasite that can live in the intestines of dogs, cats,
and man. It is seen most commonly in dogs coming out of kennel-type
situations (pet stores, shelters, dog pounds, etc.) but its incidence
is increasing. Symptoms include intermittent or continuous diarrhea,
weight loss, depression, and loss of appetite. Diagnosis is made from
a very fresh fecal specimen that must be collected at the clinic for
optimum results. A surprising number of affected animals are "occult";
that is, they are infected but are negative on these tests even with
multiple examinations. As a result, this parasite is often treated without
a confirming diagnosis. Treatment is an oral medication administered
at home. Prevention involves careful disposal of all fecal material
and cleaning contaminated areas. Humans can become infected with Giardia
so special care must be taken to wash hands and utensils.
COCCIDIA - This is also a single-celled parasite. It is seen
primarily in puppies and kittens, although debilitated adults can also
be affected. Transmission occurs by eating the infective stage of the
parasite. It then reproduces in the intestinal tract causing no symptoms
in mild cases to bloody diarrhea in severely affected pets. Diagnosis
is made from a fresh stool sample. Treatment varies greatly. Animals
showing no signs of illness are often not treated because a mild case
is often self-limiting. Pets with diarrhea are treated at home with
an oral medication. Severely affected pets may need hospitalization.
Prevention involves disposal of all stools and cleaning the pet's living
area. Human transmission is uncommon but can occur.