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Parasitic Worms in Dogs
Repeated roundworm
infection in Sheltie
Roundworms
in pregnant dog and panacur safety
Roundworms,
hookworms, whipworms and tapeworms
Whipworms
Whipworms
Hookworms
Roundworm picture
Roundworms
also see Heartworms
also see Parasites
also see Tapeworms
also see Zoonotic
Repeated
roundworm infestation in Sheltie
Question: Dr. Micheal Richards,
Our Sheltie who is 1 1/2 years old has had Roundworms so many times
we keep
roundworming him , and making sure he get 2 doses of Roundworm meds
in a 2
week period,but nothing seems to be getting rid of these Roundworms
completely.
He was dewormed 3 times as a young puppie than at 7 months old he had
Roundworms so bad he was vomiting them.It was terrible our Pokie got
so
sick.
Out Vet gave us Drontal Plus and we used it on both our Shelties to
make
sure they both got rid of them.We used it twice 2 weeks apart.Although
our
Older Sheltie has never shown any signs of roundworms nor did we see
any in
his fecals.But we did see many in Pokie our youngest Sheltie.
But after the 2nd Worming we saw no more.
Than about 3 months later I decided on my own to give Pokie Nemex 2
as he
was coughing the same way when he had Roundworms before.Sure enough
he had
Roundworms again so on to the 2nd Dose again.
Than about 2 Months or so later I decided to Roundworm again because
he had
this little coughing spells again, again he had Roundworms , so onto
another
2 doses again.
Than 2 months go by and we took 2 samples of Fresh Fecal.... twice in
that
day, to our Vet to check for Roundworms on Pokie again, and no sign
of any
Roundworms at all.
3 weeks after the Fecal exam and Pokie has a little cough again so
I give
him Nemex 2 again , and he has Roundworms again and it never showed
up in
the Fecal exam at all.
The Reason I used the Nemex 2 is because Pokie seemed to get extremely
hyper
on the Drontal Plus which really scared me so that is why I used Nemex
2 all
this time.We bought it fresh from the Pet Store and keep in stored
properly
the whole time.And we had used 2 bottles now.
All this time in our whole life we have never seen any of our dogs ever
get
Roundworms and keep them in their system so long.As a matter of fact
Pokie
is the only Dog that has ever had Roundworms that we have had in 30
year.
Pokie has that same little cough again and I highly suspect Roundworms
again, why is he never getting rid of these Roundworms do you know.I
am so
frustrated and feel terrible that our Dog has Roundworms and is never
completely ever getting rid of them.And I feel like I am harming him
giving
him Roundworms Meds all the time.
Could he have a Liver Problem or a Bowel loop that the Worms eggs are
living
in?
We had treated our Grass , and Entire yard and Sugar our Old Sheltie
has
never had a sign of roundworms ever.
Out Vet suggested that we test Pokie for Heartworms and put him on
Heartguard Monthly to kill Roundworms do you think this is a Solution
for
our Sheltie Pokie?
We have no Heartworms here and never have that is why our Vet does
not test
for Heatworms but says we have to Test before we give Heartguard.
Is they something Natural , or a Homepathic Roundwormer that is safe.
I want the Best for our Dogs and Heartguard scares me because of the
Ivermectin in it and I have heard that some Shelties have died from
it.
Answer: Barbara-
It is unusual for a dog that is over a year of age to have persistant
roundworm infestation. Roundworms can encyst in body tissues and then
be
stimulated to start a new migration to the digestive tract. The only
medication that I know of that can help with this encysted stage is
fenbendazole (Panacur Rx). I would recommend deworming with this medication
several times for three days each time, or even using it continuously
for a
period of time. It is sometimes given to pregnant bitches from the
42nd day
of pregnancy to the 14th day after the puppies are born to control
roundworms that are activated during pregnancy, so it should be safe
to
give it this long.
Then I would recommend using one of the monthly heartworm medications
to
keep roundworms under control after that. Ivermectin at the dosage
found in
Heartgard (tm) is safe for shelties. I have searched for documented
information on death from ivermectin at the heartworm prevention doses
for
both shelties and collies and have found no proven cases. I would be
interested in knowing of any that you know for sure to be factual.
Keep an eye on Pokie for evidence of increased susceptibility to other
illnesses. I am not sure that there will be a link between the inability
to
control roundworms and other immune system weaknesses but it seems
possible.
Mike Richards, DVM
3/21/2001
Roundworms
in pregnant dog and panacur safety
Question: Dear Dr. Mike,
I wrote you once before about a Pembroke Welsh Corgi bitch who had
been
bred to a young dog with lymphoma......and the bitch missed so the
issue
ending up being moot.
Well, I've bred a different bitch to a different dog, and we're nearly
7
wks into a pregnancy. Looks like a large litter, will get her
xrayed at
around day 56 to get a count.
I was wondering what your feelings are about using panacur
(fenbendazole) as described in the Merck manual for treatment during
pregnancy of roundworm infestation. The dam in question is 4
yrs old
and this is her first litter. She has been on Interceptor for
the past
three years, year round.
If you consider panacur a useful addition in a case like this, would
you
confirm the dosage? We have historically dosed at the rate of
1cc
(liquid, labeled as Safeguard for cattle) per 4 lbs. of body weight,
for
3-5 days for giardia and general deworming. The Merck manual
suggests
deworming pregnant bitches daily until the pups are 14 days old.
Or,
should we just deworm the pups later on with Nemex like most
folks do,
and we've done in the past?
I'll be talking to my local vets this coming week, but doubt they've
had
a client ask to do this before (I moved here from California, and they
seemed a little more aggressive/informed out west in this type of
situation).
Also, this bitch has a history of giardia but no recent outbreaks
(within the past year). She was vaccinated and boostered with
the new
vaccine in spring '99 by the CA vet but had outbreaks after that.
We
used metronidazole for the giardia, but it was resistant so on the
vet's advice we went to panacur which would control the outbreaks.
We
have noticed no outbreaks since moving east in fall of 99. This
probably has no relation to this use of panacur but thought you should
have the history.
Thank you, Carrie
Answer: Carrie-
Roundworms have an odd life cycle. There are dormant larvae in the tissues
of most adult dogs and these can be activated around the 42nd day of
the
pregnancy and then migrate to the fetuses in the uterus and become
active
infections. Due to this, and the apparent safety of fenbendazole for
use
during pregnancy, some reproductive specialists advise giving fenbendazole
during the the last stages of pregnancy to try to interrupt this tissue
migration. Fenbendazole must be given for three days in a row to be
effective and the dose is 50mg/kg per day for roundworms in dogs. The
suspension from of fenbendazole (Panacur Suspension tm, Safeguard
Suspension tm) are 100mg/ml, so the dose would be approximately 1ml
per 4
lbs of body weight. I haven't actually seen any studies to verify
that
this works well but it is a good theory and should be safe to try.
The
recommendations in the Merck manual seem a little excessive, to me,
but
fenbendazole is pretty safe and it probably wouldn't cause any harm
to give
it from the 40th day of pregnancy to the 14th day of gestation.
I am comfortable with deworming puppies at 2 weeks of age, using pyrantel
pomoate (Nemex Rx) and then every two to three weeks until they are
twelve
to sixteen weeks of age and deworming their mother at the same time.
This
seems to be sufficient to provide protection from health problems
associated with the worms in the puppies but may not be as good at
stopping
environmental contamination as the deworming program in the Merck Manual.
This is a link to the Center for Disease Control recommendations for
deworming programs, for another opinion:
www.cdc.gov/ncidod/diseases/roundwrm/roundwrm.htm
With the history of past problems with giardia it seems like it would
be
best to use fenbendazole for at least one of the early pre or post-partum
dewormings in the bitch, though. Just in case she is still harboring
the
organism.
Mike Richards, DVM
3/10/2001
Roundworms,
hookworms, whipworms and tapeworms.
Question: I have a stray here in a 6x12' pen. It was discovered
she had worms
yesterday and she was at the vet overnight getting medication and one
more
dose I will give her tomorrow. My BIG worry is that even though
I picked up
all of her stools and disposed of them in a plastic bag, before I knew
she
had the worms I walked around the pen and wonder if I have spread the
larva/eggs into my yard and house where I have six dogs of my own.
I have
sprayed her area with 1 gal water and 1 cup bleach solution and covered
the
ground with a tarp as it was raining. (I hate to see what she
does to it
tonight!) What other precautions can I take? She gets another
worm dose in
three weeks but I believe I can send her back to CPA in 7 days when
her
shots (parvo, etc.) take effect. I am worried sick. How
soon should I have
my dogs checked for worms? They sometimes get tapeworms but I
don't believe
they are as contagious as the other types and usually get rid of the
(tapeworms) easily.
Thank you, Dixie
PS: How long do the larva/eggs survive on the outside?
Forever?
Answer: Dixie-
There are four types of intestinal worms that dogs get on a fairly regular
basis. They are roundworms, hookworms, whipworms and tapeworms.
Most dogs have roundworms (Toxocara canis, cati or leonina) at some
time in
their life. This worm can be passed to puppies while they are in the
uterus
and while they are nursing. Eggs that are passed can develop into infective
larvae that are capable of directly infecting another dog. The eggs
may
also infect an intermediate host, such as earthworms, mice, rats and
moles
and then when this creature is eaten by the dog develop into adult
roundworms in the dog. Roundworms have a strange life cycle, migrating
out
of the intestine and into the lungs (and other organs) before returning
to
the intestines. Once infected, a dog may pass millions of worm eggs
in the
stool. The eggs can live for several months in the environment. They
are
sensitive to ultraviolet light, so pens which are exposed to direct
sunlight do not support the life cycle of the worm as well as more
protected pens. Roundworm eggs can be killed by using aqueous iodine
solution (Clinics of North America, November 1987) but are not killed
by
chlorine bleach, although it is supposed to remove the sticky outer
coating
of the worm, making it easier to cleanse them from infected areas.
If your
adult dogs are on heartworm prevention medications there is a good
chance
that they are being dewormed with a medication that can kill roundworms
on
a monthly basis, which should be sufficient to prevent any real worry
over
them getting infected, especially since dogs become more resistant
to
infection with roundworms as they get older. Cleaning up stools daily
prevents the spread of the eggs pretty efficiently and is a good practice
to prevent infections.
Hookworms (Ancylcostoma or Uncinaria) are less common than roundworms
but
are still a major problem in southern areas of the U.S. (Ancyclostoma)
and
not too uncommon in the more northern areas (Ancyclostoma and Uncinaria).
Hookworms eggs develop into infective larvae which can pass through
the
skin or be ingested and cause infection. The eggs and infective
larvae are
susceptible to sunlight and drying. There used to be a product sold
that
would treat infected dirt pens and kill the hookworm eggs but I have
not
seen it for at least ten years. The heartworm prevention medications
Heartgard Plus (tm), Revolution (tm) and Interceptor (tm) kill hookworms,
so dogs on these preventative medications are also being treated for
hookworms monthly, which should be sufficient to prevent problems with
them, as well. If you are not in a heartworm area monitoring stool
samples
every few months and treating if you find evidence of infection should
be
sufficient to prevent major problems from these worms. Cleaning up
the
stools daily also helps to prevent the spread of hookworms. I do not
know
how long hookworm larvae live in the environment, but I think they
are not
as hardy as roundworm eggs and larvae. There is no intermediate host
to
worry about, either.
Whipworms (Trichuris vulpis in dogs) has the most environmentally resistant
eggs of all the worms. The eggs of this worm can live for longer than
a
year in the environment. They are susceptible to drying and sunlight.
The
Clinics of North America issue recommends treating concrete pens with
a
horticultural flame gun to kill the eggs, which I suppose might work
on
dirt, as well. This worm is killed by milbemycin, the ingredient in
Interceptor (Rx) heartworm prevention but is not killed by the other
monthly preventative medications. Therefore, it is more important to
monitor fecal samples for evidence of the worm. The time from infection
to
the appearance of worm eggs in the stool is over two months, though
-- so
it can take awhile to know if this worm will become a problem when
there is
potential contamination of the soil. Whipworms are harder to kill than
roundworms and hookworms (or at least fewer medications do it
successfully). We use fenbendazole (Panacur Rx) for whipworm therapy
but
there are other medications that will work. Your vet will have one
that he
or she likes to use.
Tapeworms are usually acquired by eating infected fleas (Dipylidium
caninum) or small rodents or rabbits (Taenia species). Good flea control
eliminates most problems with tapeworms except in dogs who are allowed
to
run free or to hunt small animals at times.
Even though it may not be possible to rid your yard and pen of the worm
eggs easily, there isn't a lot of reason to worry excessively over
the
worms. In many cases preventative measures are already being taken
due to
the use of heartworm medications and when this is not the case, checking
stool samples and treating in infections and cleaning up the stools
on a
regular basis should be sufficient to clinically prevent significant
problems with worm infestations.
Mike Richards, DVM
2/4/2001
Whipworms
Question: Dear Dr. Mike:
Myfriends 9 month old mixed breed has had no energy for four days, she
broke
out of her kennel four days ago, came back after 8 hours with a few
scrapes
and not acting like herself.
My vet diagnosed her with whipworm and prescribed the meds for it.
But I am
now wondering why she is still not herself.
INFO:
She lets out a little whimper when she jumps off the couch. Sometimes
whimpers when she is just laying still.
She was spayed 1 month ago.
She is up to date on all her shots.
She is on Heartguard, but I am switching to Interceptor.
She did have diarrhea, but not anymore.
She has not puked.
So, I would like to know if whipworm would cause her to not have any
energy
or cause her pain?
Thanks
Answer: J-
It isn't too unusual for whipworms to cause a dog to feel tired or to
cause
diarrhea but it doesn't usually cause pain associated with things like
jumping off of the couch.
It isn't too unusual for a dog that goes off on a jaunt to run hard
enough
to cause muscular soreness or to exacerbate a problem like hip dysplasia
and make a dog lame. It also isn't too unusual for dogs that disappear
for
a while to suffer a traumatic event, like being hit by a car or fighting
with another dog. Sometimes, it takes a day or so for an injury to
show up
from a traumatic event.
If she is still sore on Monday, it really would be a good idea to think
about getting her rechecked by your vet, just in case there is an injury
or
some other problem contributing to her behavior.
It isn't unusual for an exam to show a problem that can explain all
the
symptoms evident at that time when there are actually other problems
that
don't show up or that aren't recognized because a plausible explanation
is
found and so more involved diagnostic tests aren't run. In these situations
it is important for you to stay vigilant for futher problems, which
you
have done.
If she still feels under the weather tomorrow it would be a good idea
to
schedule a recheck with your vet.
Good luck with this.
Mike Richards, DVM
12/12/99
Whipworms
Q: My vet tells me my dogs-
boxers- have whipworms, a heavy infestation
and that Heartguard Plus will take care of the problem, but I've
heard
different from other breeders. I can't find anything on your website
about
it. Could you please give me some more info about whipworms. I've read
that they are very hard to get rid of. Whipworms are not listed on
the
Heartguard insert.
thank you Chris
A: Chris-
Meriel (manufacturer of Heartgard) makes no claim that it will kill
whipworms and I do not think that the active ingredient, pyrantel,
is a
good choice for whipworms, either. In this case, I think that you need
to
check again with your vet to make sure that he or she isn't having
one of
those days when a person just gest off track or to be sure that you
did
hear the instructions correctly. I think you do need an additional
medication. Whipworms can be controlled using several safe medications,
such as Panacur (Rx).
Mike Richards, DVM
Hookworms
Q: Hi my name is Janet. I really like
your web site. It is very useful in my
research for my parasite paper. However, I think you could add
hookworm to
your list of parasites.
Janet
A: Janet-
There are four species of hookworms that infect dogs and cats in the
United
States. They are Ancylostoma braziliense, Ancylostoma caninum, Ancylostoma
tubaeforme and Uncinaria stenocephala. In dogs, A. caninum is the most
common hookworm and causes the worst disease. In cats, A. tubaeforme
is
more common but is less likely to cause severe disease than A. caninum.
Dogs in the Northern states and in Canada are more likely to be infected
with U. stenocephala as it prefers cold climates and A. caninum prefers
warm climates.
A. caninum hookworm infestation in dogs can lead to severe anemia,
especially in puppies. These hookworms have big appetites and attach
to the
intestine and feed on the dog's blood. The other three types of hookworms
are less likely to cause severe anemia but it is a potential problem
with
them. Signs of hookworm infection include weight loss, pale color,
black or
tarry looking stools, weakness, anemia and death. In areas in which
hookworms are prevalent there can be skin disease in pets associated
with
exposure to the larval worms as well.
Hookworms can be acquired from the mother's milk, from penetration of
the
skin by hookworm larvae in the environment and from eating hookworm
larvae.
Some vets think that it may also be transmitted during pregnancy from
mothers to puppies but this is controversial and I believe that it
has been
ruled out in cats.
One of the problems with hookworms is that they can accidentally infect
humans. This creates a problem called cutaneous larva migrans, which
loosely translates to worms migrating through the skin. Humans pick
up the
hookworm larvae from areas contaminated by dog feces and they penetrate
the
human's skin just like they would the dog's. Since they don't belong
in the
human they don't develop into adults but just migrate around in the
skin,
causing sores and inflammation, until they die. This is a good reason
to
keep dogs and cats from defecating in playground areas, beaches and
other
places where people's skin is likely to come in contact with the ground.
Fortunately, the monthly heartworm preventatives are also effective
at
controlling hookworms and can provide a measure of protection against
the
possibility of the cutaneous larva migrans syndrome occurring in the
humans
that own dogs and cats on heartworm preventative medications. In areas
in
which heartworms are not a problem but hookworms are, it is a good
idea to
consider having a pet's stool examined for the presence of worm eggs
once a
year and when clinical signs that may indicate infestation occur.
We will add this information to our site, too. Thanks for the suggestion!
Mike Richards, DVM
Roundworm picture
Bob from Queensland, Australia sent us a great roundworm picture.
The worm was passed by his new Border Collie X puppy, Cane. Cane was adopted
from the local Shelter and is 12-14 weeks old. The screw in the picture
is 30mm or 1 1/4" inches long.
Roundworms and people (Zoonotic)
The roundworms most commonly associated with pets are the Toxocara and
Toxascaris species of roundworm (there are many, many species of roundworms).
These two species of worms are transmitted to humans through the ingestion
of roundworm eggs which contain infective larvae. Typically it takes between
one and three weeks for these eggs to develop from the time they are "laid"
to the time they contain an infective larvae.
Dogs can acquire roundworm infections from their mothers while in the
uterus. Therefore, it is important to begin to deworm dogs at 2 weeks of
age. To the best of my knowledge cats are not able to transfer roundworm
infections to kittens in the uterus and therefore it is usually recommended
that deworming begin at about 6 weeks of age in kittens as it takes about
that long for the infection to reach the stage where deworming medications
are effective. Dogs should be dewormed every 2 weeks until they are about
3 months old .
There is some fear that roundworms may be passed by a puppy licking
the owner. While the transmission rate through this avenue of infection
is probably very very low it is still a good idea to observe good hygiene
and wash hands and faces after playing with the puppy.
Once the initial infection is treated properly it is a good idea to
occasionally check a stool sample for the presence of worms or to consider
prophylactically administering deworming medications if the situation seems
to warrant it.
Occasionally a physician will advise one of my clients to put their
cat outside to reduce the risk of infection with Toxocara or toxoplasmosis.
I truly believe that this advise is wrong. An indoor cat is unlikely to
pick up an infection with roundworms or toxoplasmosis as there is no ready
source of the worm eggs indoors. The litterpan is easily cleaned and most
people don't dig around in the pan much. On the other hand, an outdoor
cat is easily reinfected with roundworms from the soil and is very likely
to defecate in places like gardens where people do tend to dig around a
lot. If you have cats, or even if you don't, it is a good idea to wear
gloves while gardening. Clean vegetables grown in the garden before eating
them. For most people, these preventative measures are just normal procedures
but it is good to know there is a reason for all this caution!
Roundworm infection in people can cause "flu like" syndromes, with fever,
liver enlargement, changes in the white blood cell count and differential
and in some cases eye damage. I do not know for certain how the diagnosis
of roundworm infection in a human is made. Your physician will probably
know, though. It is unlikely that you have been exposed to infective eggs
but if you or a family member experience an illness it would be worthwhile
to inform your physician of this possibility.
Mike Richards, DVM

Last edited 08/30/02
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