Fleas and Ticks
Table of Contents
Cindy Moore, Copyright 1995-1997 by Cindy Moore. You may
download a copy for your personal use. To redistribute, please ask.
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This document is provided "as is" -- no warranty, express or
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All editing is mine, and any errors should be attributed to me. I
welcome all additions, corrections, and suggestions for this file.
Please send email to me at any of the addresses at the end of this
Thanks to: Sandi Ackerman, Edwin Barkdoll, Shari Bernhard, Maggie
Bonham (aka Sky Warrior), Jon R. Buyan, Brad Christofferson, James
Coggins, William S. Currie, Eric De Mund, Bill Dittman, Gene Dolgner,
Marc Gabriel, P.K. Geschwent, Jim Graham, Gary Greene, Paul Jackson,
Kathy Johnson, Marget Johnson, Renee Johnson, Kay Klier, Jon Krueger,
Kerry Kurasaki, Ellen McSorley, Dana Massey, Andy Michael, Liza Lee
Miller, Lloyd E. Miller, Peter Nichola, Jolly C. Pancakes, Jeff
Parke, Sonya Perkins, Paul Quinlan, Christine Rassmussen, Edward Reid,
Keith Silver, Susan R. Smart, Orca Starbuck, Marlene Teague, Julia
Tien, Laura Toms, Lesa Hobright Turner, Michael Waldvogel, Janeane
L. Yeh and Frank Yeh Jr., and Rich Young for their comments and
The initial nucleus of this article may be found from a posting by
Dave Butler, who posted it sporadically a few years ago and I saved
a copy in mid 1992. It has since expanded far beyond this initial
article, but it did provide the initial impetus.
Dr. James Coggins did a presentation on ticks in Wisconsin from which
I got much of the material on ticks and Lyme disease.
Finally, I'd like to thank my own dogs for providing me with hands on
experience with ticks. :-)
Fleas can enter the home in many ways, even if your pet is not or only
rarely allowed outside. They can hop in from your yard, hitch a ride
on you, or even be left over from previous inhabitants (larvae can
remain dormant for astonishingly long periods of time under a variety
Since fleas can be carriers for worms and diseases, keeping your pet
flea-free helps to keep it healthy. In addition, many pets and people
are allergic to flea-bites.
To check if your pet has fleas, part its hair and look for:
You may also see "flea dust," fleas, or even larvae on your pet's
- Small bits of brown "dust," attached to the fur itself. The fleas
excrete digested blood. See if the dust dissolves into a red
liquid upon contact with a wet paper towel.
- Skin Irritation: flea bites or scratching and biting may leave
red, irritated skin, and even bald patches in bad cases.
- Small, fast moving brown shapes are fleas.
- Or, use a flea comb and see what you get.
Dried blood in its ears may indicate ear mites and you should consult
your vet to find out what the problem is.
Conventional wisdom and older studies that studied rat fleas suggest
that fleas spend only part of their time on your pet; this is not
true. There are different varieties of fleas, and the primary flea
infesting dogs and cats in North America and large areas of Europeis
the cat flea (yes on dogs, too). This flee, not as well studied as
the rat flea actually spends all of its adult life on the host under
normal conditions. Eggs are laid on the host and drop off into the
environment. Thus you can often find eggs wherever your pets spend
time: on their bedding, through the house, in the backyard.
A good preventive method is to put down towels everywhere your pet
normally lies and then wash those towels once a week. Deposited flea
eggs are therefore cleaned out regularly. Regular vacuuming and
emptying of the vacuum bag also helps, independently of any method or
methods you choose to do, since that eliminates or reduces food
sources for the larvae.
There are several ways to kill or discourage fleas. Some are synthetic
chemicals, some are considered "natural", and both work with varying
degrees. No one method is 100% effective, and you will almost always
have to combine several approaches to get the results you want. Some
methods are applicable for indoor pets, but useless for indoor/outdoor
pets. You need to choose the set of approaches that best addresses
Keep in mind that there are regional differences among fleas: what
works well in one area may not work well in other areas. You should
consult a LOCAL vet, vet tech, or dog groomer to see what is known to be
effective in your area. If you thinkyou're getting biased opinions,
ask several people and see what they concur on. Don't rely on the products
available at your
local store; there are too many that are just distributed nationally.
Finally, you may find that you need to switch your approaches around
from year to year. If you use the same product several years in a
row, you may find the effectiveness lessened. Additionally, some
years are worse than others, depending on the previous winter, and you
may need to strike earlier with stronger methods some years and relax
a bit more with milder methods another year.
You must keep in mind the life cycle of the flea. From egg to larvae
to adult is between three to six weeks: to get rid of fleas in your
house, you must break this cycle. As a practical matter, this means
you will almost certainly have to repeat your efforts in several weeks
to catch the fleas from the larvae that didn't get destroyed the first
time around. This is also why it is important to address the problem
of the eggs and larvae as well as the adult fleas.
After taking a blood meal, fleas either lay eggs on your pet or in its
surrounding environment. Eggs on your pet are often shed onto its
bedding or into the carpet. A pair of fleas may produce 20,000 fleas
in 3 months. Eggs hatch after 2-12 days into larvae that feed in the
environment -- generally on digested blood from adult fleas and other
food matter in their environment. The food required at this stage is
microscopic, and even clean carpets often offer plenty of food to the
larvae. The larvae are little wiggles about 3-4 millimeters long, you
may see some if you inspect your pet's bedding carefully. Larvae molt
twice within 2-200 days and the older larvae spin a cocoon in which
they remain for one week to one year. When in this cocoon stage the
young flea is invulnerable to any kind of insecticide and to low, even
freezing, temperatures. Only sufficient warmth and the presence of a
host can cause them to emerge. This long cocooning period explains
why fleas are so difficult to eradicate.
Having your carpets professionally cleaned WILL NOT get rid of the
fleas, unless they use something that is meant to kill fleas.
However, it will remove much of the eggs, larvae and the food that the
larvae feeds on, so it can be useful in conjunction with other
Remember that carpets, rugs, and upholstered furniture are the prime
places for depositing flea eggs. Some people have success ridding
their home of fleas by removing their carpets and replacing with
linoleum or hardwood floors. This may not be a feasible option for
These tend to be of the "folk-remedy" type. Some people swear by
them, others do not get any results. Some are actually toxic. They
tend to work better at keeping fleas away rather than killing or
eliminating present infestations.
There are a number of companies that will spray your house and
typically they have guarantees such as "flea free for a year" (or they
will reapply free of charge). The best known one is probably
FleaBusters applies a product to your carpet that kills
all the fleas and eggs. Many people report that the results last for
longer than the guaranteed year. Other people have pointed out that
the product FleaBusters uses is Terminator (see below), and applying
it yourself can be a significant savings over what FleaBusters
- You can buy cedar shampoo, cedar oil and cedar-filled sleeping mats.
Cedar repells many insects including fleas.
- Let outdoor pets sleep on a well-used horse blanket. Equine-l
folks have confirmed that horses get ticks but not fleas, and
cats using horseblankets in *current* use seem to have fewer
- Fleas love dry skin: prevent dry skin by giving your pet Linatone
(or any vegetable oil) with its food and avoiding excessive
- Pennyroyal (the herb and the oil) is often touted as a natural
flea repellent: only the fresh or dried leafs are safe. The oil
is actually highly toxic to animals and humans (it has a long
history as an abortifacent, for example). There is an article
about this in the AKC's Gazette, July 1992. Also, Journal of
the AVMA, v200 n6 March 15, 1992.
- Garlic and Brewer's Yeast: Feed it in small doses to your pet and
and the resultant body odor may repel fleas. You can get it either
in powder form or tablet form, at varying expense.
- Orange or lemon peel boiled and simmered in water makes a flea dip
after it cools. Do not use this on cats, however (don't know
about ferrets). Rinse well.
- 60 ml of lavendar oil mixed with 2.8 liters of rock salt can be
placed under furniture and rugs.
- Eucalyptus leaves can be left under furniture and rugs. Also, a
eucalyptus wool wash [a product for washing wool made from
eucalyptus, available in Australia, perhaps elsewhere too] when
washing the dog may help.
- Rub bruised fennel foliage into the dog's coat. Growing it in
the yard discourages the establishment of fleas there.
- You can plant marigolds outside in your garden. This has the
additional benefit of repelling a variety of other bugs.
- NuPo offers a "flea trap" that uses heat to attract fleas to a
sticky pad, kind of like "flea paper." Homemade variants,
considerably less expensive, include leaving out detergent-laced
dishes or jars of water near nightlights at night. This approach
works best in severe infestations but is not likely to eliminate
- Food supplements, there are several on the market besides
the "conventional" brewers yeast and/or garlic. One is
Hop Off. Again, they appear
to work for some dogs and not necessarily others.
- Often useful in conjunction with other methods is to cover up your
pet's ears and around the neck with a wet towel and have it lie in
a tub of cool water for a while. The towel prevents migration of
the fleas to the head. Add just a little detergent to the water
(a teaspoon or a few cc's is enough) to make sure the fleas drown.
Obviously, your pet must be amenable to lying in water for 15
minutes or so. This can be done as an alternative to dipping; but
like dipping it will not solve the larger problem of the flea
- A similar method is to prepare a warm bath in the kitchen sink (or
tub) with just a little baby shampoo and submerge the pet except
for the head. Hold the vegetable sprayer (or spray attachment)
about an inch away from your pet (under water) and literally blast
the fleas off. By doing it under water, it keeps the fleas from
simply being blown to another part of the pet. The head has to be
sprayed while out of the water. Fleas will float to the surface
but drown because of the bit of shampoo in the water. This may
help remove eggs as well. Again, this technique only works on
animals that are amenable to lying down in water.
You can spray your house. There are a number of commercial foggers
and other devices which you set off in your home. Generally, you and
anything live will have to vacate for a period of time. This can be
effective; it depends on if the chemicals involved will kill fleas,
flea larvae, or both. Your vet will be a good source of information
on effective brands, or you can have this done professionally.
Remember that a hand-held sprayer will be more effective than a
fogger-type application simply because you can make sure all the
hard-to-reach areas are properly treated.
In general, pyrethrins are "low intensity", relatively safe, and break
down quickly (some on contact with sunlight). They can normally be
used safely with puppies, kittens and in sensitive conditions.
Pyrethrins are from chyrsanthemums, and manage to be highly toxic to
fleas but not to people or dogs. It's very safe. Permethrins are
synthetic pyrethrins and have the additional benefit of a residual
effect for several days.
Organo-phosphates are "heavy duty" and last longer. They should be
used with caution as they are usually toxic to people and animals.
The Insect growth regulators do not kill adult fleas, but they have
little or no toxicity to non-insects as they very specifically target
the flea larvae, preventing its transition to adult stage.
When treating the area surrounding your house, remember that fleas are
not found in your driveway gravel or in the open. The larvae do not
survive high temperatures. They are found in shaded areas, like under
porches, decks, car ports, at the edges of woods, and especially in
places where your pets lay down outdoors.
- Precor: (methoprene)
- This is an insect hormone that interrupts the
life cycle of fleas by preventing flea larvae from maturing. It is
not a poison, even to fleas, but they cannot reproduce. It's used
as an environmental spray either by itself (in which case it will
take several weeks to show much effect) or combined with adult
pesticides (like pyrethrins) for a quick wipeout.
Because it's a hormone, it's thought that fleas can't become
resistant to it. However, methoprene resistance has been reported
in experimental population of fleas. If you're getting poor results
with Precor (=methoprene), you might try Fenoxycarb.
You can buy the stuff at your local hardware/gardening store, and
spray the diluted (according to directions) liquid everywhere in the
house. This will not kill fleas by itself unless you combine it
with something immediately lethal, but it will break the lifecycle
and the fleas will go away in a few weeks as the mature ones die and
the immature ones fail to develop. Such an application lasts about
4-5 months. Precor cannot be used outside because it breaks down
rapidly in sunlight, but there are new formulations, such as
Fenoxycarb, that show promise for outdoor use.
Precor is most often combined with other agents, like pyrmethrins.
Currently available are powders, sprays, and foggers all containing
the ingredient. It can be difficult to find a source of pure
methoprene. One mail-order source is Gardens Alive! It's called
Vigren and is $9.25 per oz concentrate (mix with 1 gallon of water,
covers 1500 sq. ft) or $7.95 for three or more. Address below.
- This is a pure form of fenoxycarb, an IGR. It can be used
outdoors since it doesn't react to UV like methoprene does. It is
available through Kristull Products, 8708 Grelle Lane, Autin, TX
78744; 800-658-6699. Many products now contain fenoxycarb, but
Torus seems to be the only undiluted form available. Due to
company buyouts, Torus has been discontinued from the market, though
there is still some stock available from distributors.
- This is a Torus like product against fleas (and fire ants).
- This is microencapsulated pyrethrins (low toxicity to
mammals). This works well in conjunction with methoprene. Spraying
your home with this combination should be good for about 5-6 months
before reapplication is needed. Use the Sectrol Pet and Household
Flea Spray #1495 for the pure micro encapsulated pyrethrin product
(3M has a variety of "sectrol" products). Expensive.
- This comes in both a spray (for the house) and a dip for the
immediate problem on your pet. The smell is reported to be minimal
and the effectiveness high. You only need to leave the house for
1/2 hour to allow the spray to dry (rather than up to four hours for
other sprays and foggers, for example). Duratrol consists of micro-
encapsulated chlorpyrifos -- essentially Dursban in "tiny time pills."
- When choosing a fogger, note that the directions call for one
can per X no. of UNOBSTRUCTED square feet. In practice, that means
one can per major room. You can increase the effectiveness of the
spread of the fogger by setting up fans to move the air around
before you trigger the foggers. If you have a forced-air furnace,
set the fan to on and thermostat to off (turning the thermostat off
ensures that the heaters do not kick in; most fogging sprays are
flammable or explosive). Foggers
have a real problem in penetrating enough to do any good, though.
They just don't reach under furniture and other inaccessible places.
For those with outdoor pets, diatomaceous earth, boric acid and silica
aerogels can be used to treat your lawn for fleas and ticks. These
chemicals were lauded by the Apr 92 Sunset magazine in their list of
least toxic chemicals, sprays and dusts, which were discussed for
those people who want to control pests more naturally. These are not
poisons, and kill by clinging to, scratching and and destroying the
waxy exteriors, or dessicating the pests. Sunset does point out
that these chemicals should not be inhaled as they will irritate or
abrade the lungs in the same way (which isn't a big problem once
they've settled into your lawn). Diatomaceous earth is an abrading
agent (much like borax). Use natural grade rather than pool grade
diatomacious earth. Boric acid is also a abrading agent. Silica
aerogels are dessicants, and kill the insects through dehydration.
It is recommended that these chemicals be used in powder form to kill
fleas and ticks.
For an immediate flea problem, you can bath your pet with a
flea-killing substance to get rid of the fleas on its body. But
remember, such "dips" usually sting when applied to open irritations.
Animals have been known to bite, climb up your arm, and even urinate
all over themselves, so be prepared!
- You can use Dursban for ridding the yard of fleas. Home
Depot will have the generic stuff. Spray according to the
directions on the label. This is fairly toxic stuff. The generic
name is Chlorpyrifos.
- This is a new product for outdoor treatment. "Bio Flea
Halt" and "Interrupt" are two brand names -- probably others exist.
Nematodes are bugs that eat fleas. You apply it to your backyard
with a pump sprayer; hose sprayers will also work. [Not sure about
details of application: do you apply to grass? dirt? what about
decks? effect on existing plants?] Toxicity to humans/dogs is
non-existent, early studies show a good degree of effectiveness.
Be very careful to only dip animals that are at least two, preferably
three months old, and be especially careful to use appropriate dips.
That is, do not use dips marked for dogs on cats!
Avon's Skin-So-Soft lotion is reputed to repel fleas (as well as
mosquitos on human). After bathing your dog, put some lotion in the
rinse water. They will smell like the lotion, and the application
will last for a few weeks. This may be a problem for pets that groom
themselves. Another way to apply it is to put a 1:1 lotion:water mix
in a spritz bottle and mist your dog with it. Some people report
excellent results and others do not.
Dipping alone will NOT solve the more general problem of the flea
Flea combs with fine teeth that snag fleas are commercially available.
It is helpful to have a small dish of ammonia-laced water on hand to
kill the fleas on the comb rather than trying to nail each one by
hand. Alternatively, mix a few drops of detergent into the dish of
water so that there is no surface tension and fleas dropped into the
treated water will drown. Use a metal comb; the plastic ones are too
flexible and allow the fleas to escape.
You will typically find the most fleas along your pet's back, groin
area, and at the base of the tail.
This by itself will never rid your pet from fleas since flea larvae
may also be in bedding, furniture and carpet. It is, however, a useful
way to keep an eye on the flea population, and if used as a preventive
measure can keep them in check. If you have a major infestation, though,
you will have to get rid of most of the fleas before you can use just
a comb on your pet.
Flea powders are handy, but there are many types and some are rather
poisonous. Check the poisonous list below for ingredients that cause
serious problems (for cats). When using powders, it is not enough to
just powder your pet: powder its bedding, and under furniture cushions.
You may want to add some to a discarded vacuum cleaner bag especially if
it will sit in the trash for a few days, but don't
run a vacuum with flea powder in the bag. That will probably
spray it in the air, potentially toxic to sensitive animals or humans.
Do not let your pet ingest flea powder of any sort. This can be
tricky with pets that groom themselves, such as cats and ferrets.
With dogs, if you brush the powder in, your dog will not ingest
much if any powder.
Also known as sodium polyborate, sodium tetraborate, sodium borate.
The chemical is related to boric acid. This is present in a variety
of household products. Sprinkling 20 Mule Team Borax, the kind you
use in laundry (*not* the hand soap Boraxo; the soap added to can be
toxic to your pet) on the carpet and upholstery will dry out the
deposited flea larvae. The procedure is to vacuum the house, sprinkle
borax or salt using a sieve on carpet and upholstery (and under the
pillows, under the furniture); sweep with a broom to settle the borax
into the carpet and then vacuum again. Some people leave it on for a
few days before vacuuming, but this runs the risk of abrading the
surface of the carpet. Don't let your animals eat the stuff. If you
use borax, you may need to adjust for this when cleaning your carpets
by using less soap. The effects of a borax treatment seem to last
about a year or so.
Drawbacks: The chemical borax is abrasive, and 20 Mule Team Borax may
abrade your carpets. In addition, there are documented cases of
long-term low-level exposure to sodium polyborate resulting in
conjunctivitus, weight loss, vomiting, mild diarrhea, skin rash,
convulsions and anemia and other similar allergic reactions in humans.
If you're using borax as flea control, and your pets (or family) are
showing loss of appetite, eye or skin problems, anemia or kidney
problems, you may want to switch to another flea control method and
see if their health improves. Do not apply it to damp carpets as it
can take the color out.
Borax is NOT advisable where you have pets which groom themselves,
e.g., cats and ferrets. They can ingest enough to harm them if the
borax is not settled deeply enough into the carpet (October 1992 of
Dog Fancy). Symptoms of acute poisoning include diarrhea, rapid
prostration and perhaps convulsions [these occurred when borax was
scattered openly for cockroach control].
There are various products that are applied in the same way, such as
PEST-X. Check these types of products to see if they contain borax or
boric acid. If so, the above commentary applies to those products as
well. Otherwise, check the ingredients against the other ingredients
Some people use salt instead of borax. Provided that you do not live
in high humidity areas, this is an alternative. Since salt absorbs
water, salt in carpet in an unairconditioned house in Florida (for
example) would mean a damp carpet -- later rotted or mildewed.
A cheap source of boric acid powder is
in hardware stores. A 5lb can of 100% boric acid powder is about $22;
a 30lb can $54. Customer service # is 800-242-9966.
Put flea powder in the vacuum cleaner bag to kill any fleas that you
vacuum up, otherwise they will crawl back out. You should change the
bag in your vacuum cleaner after a round of flea-cleaning in any case.
Moth balls can also be used, but they are pretty toxic. Sometimes
people put (cut up) flea collars in the bag, but it is not clear that
this is effective, and if the collar contains dichlorvos, is NOT
See Consumer Reports, August 1991. Flea collars aren't effective
and may even be bad for your pet's health. Some of the herbal ones
smell nice and that's about it.
Ultrasonic and electronic flea collars are not known to work.
Very young animals can die from overinfestation of fleas. They are
small enough that they can become dangerously anemic within hours, and
are young enough that they will be poisoned by dipping chemicals.
Consult your vet immediately if you have a less than 8-10 week old
kitten or puppy with a bad case of the fleas. Do not attempt to
"dip" them, you can easily kill them this way.
Symptoms of anemia: if flea-infested baby animals become lethargic,
weak, and pale, you may have *only hours* before they die. A good
test for anemia is to take your finger, lift the upper lip, and press
gently but firmly into the upper gum. The gum will turn white for a
moment and then return almost immediately to a pink color. If the gum
stays white for more than a couple of seconds, anemia is indicated.
Take them to the vet *now*.
If they do not yet appear anemic, use a flea comb on them. You should
take steps to prevent infestation by keeping the mother clear of
fleas, and regularly (at least every other day) changing and
laundering the bedding. While you should not dip them in chemicals,
giving them a plain soap-and-water bath can help remove the fleas from
their body: wash the bedding at the same time and then use the flea
comb regularly to keep fleas from taking hold again. The mildly
insecticidal shampoo Mycodex (tm) can be used on kittens, but requires
flea combing afterwards anyway because of its mildness.
From Orca Starbuck:
Most flea shampoos, sprays, and powders are not cleared for use on
pregnant, nursing or young animals. In addition, the act of bathing,
spraying, or powdering a pregnant or young animal can frighten or
chill the animal. So most vets are hesitant to recommend ANY course
of action if you have pregnant, flea-infested animals. However:
According to Steven A. Melman and Karen L. Campbell's "Flea Control"
(John R. August, ed. 1991. Consultations in feline internal
medicine. WB Saunders & Co., Philadelphia. ISBN 0-7216-2226-7:
Chapter 9), pesticides that have caused serious or fatal illness when
used ON cats at dosages effective against fleas are:
Low concentration pyrethrin products (or allethrin, like mycodex) ARE
considered safe. In "Feline Husbandry" pyrethrin is the only flea
poison included in a list of chemicals and drugs that are known to be
safe during pregnancy. Methoprene is also considered safe, although
its use is new enough that it doesn't appear in many of the texts.
Zodiac pyrethrin + methoprene spray for cats is considered safe for
pregnant and nursing cats and kittens that are at least 24 hours old!
The same is true for the similar spray for dogs. Likewise, the Zodiac
premise sprays are safe for use where pregnant and nursing animals and
young animals are housed, as long as the spray is allowed to dry
before the animals are introduced back into the area.
Since spray can often be upsetting to the mother cat, a paper towel
which has been sprayed with Zodiac spray for cats until it is about
1/2 saturated is better. Rub the towel all over the queen (except for
her face and nipples) and comb out with a flea comb, and repeat the
treatment a week later.
If there are still problems with fleas once the kittens are born, it
is quite safe to do the same treatment on the kittens about once a
week, starting at a week of age.
The following flea-cides used ON dogs are NOT approved for use ON cats
(though they're all OK'd for indoor environmental use):
- Carbaryl (Sevin)
- Chlorpyrifos (Dursban)
- Dichlorvos (DDVP, Vapona)
- Dioxathion (Delnav, Deltic)
- Naled (DiBrom)
- Phosmet (=prolate, Kemolate)
- Propxur (Sendran, Baygon)
- Pyrethrins (but microencapsulated pyrethrins have no listed problems)
- Ronnel (=Korlan)
- Tetrachlorvinphos (=Rabon)
The following have been reported to cause serious illness or death
when used ON dogs:
- Amitraz (Mitaban)
- Bendiocarb (Ficam)
- Chlorphenvinphos (Supona)
- Chlorpyrifos (Dursban)
- Cythioate (proban)
- Diazanon (Spectracide)
- Fenthion (Prospot)
- Methoprene (Precor)
by Sandi Ackerman
- Carbaryl (Sevin)
- Chlorpyrifos (Dursban)
- Dichlorvos (DDVP, Vapona)
- Fenthion (Prospot)
- Phosmet (Prolate, Kemolate)
- Pyrethrins (but not microencapsulated)
- Ronnel (Korlan)
- Tetrachlorvinphos (Rabon)
There's a controversy as to which type of flea products are safest for
our rabbits. The House Rabbit Society has always said to use a powder
that is safe for cats/kittens and in this area of the country our
veterinarians have recommended pyrethrin based powders. However,
we've recently discovered that while our veterinarians in Washington
state are saying to use products that contain pyrethrins,
veterinarians in other parts of the country say to use products that
contain 5% Carbaryls.
What I've found after considerable research is that there are no
specialists who will make a written statement one way or the other as
to which product (one, both, neither) is safe for our rabbits. This
is because there have been inadequate studies done on rabbits (thank
goodness)! But what's a person to do?
I've searched through Medline, which is an on-line medical database
containing data going back to 1966. There are many of studies out
there about pyrethrins and carbaryls, but the question is: how to
interpret them? I've tried to get manufacturers of flea products to
talk to me -- no luck. So after gathering all the data that I could
find, I called the National Animal Poison Control Center (NAPCC) to
verify the following information.
Pyrethrins are considered safe. These are insecticides derived from
plants, but in some cases where the dose is too high, they can cause
tremors, seizures and death. They act rapidly and have "some
Pyrethroids are synthetic derivatives of natural pyrethrins and are
considered to be "more effective insecticides and are less toxic to
mammals than the natural pyrethrins". Allethrin (a synthetic) is
said to be safer than natural pyrethrins.
Carbaryls are considered safe and are used on vegetables in our
gardens (Sevin). But they too can cause convulsions and death if too
high a dose is used . They remain effective from one to three
The database at the NAPCC contains no reports of problems in rabbits
from either the pyrethrin or the carbaryl powders.
It's not these insecticides which are the problem, but rather the
enzyme inhibitors in the products! The following are common enzyme
inhibitors, also known as synergists, which may be found in flea
These synergists may be added to the flea powder/spray in order to keep
the flea from being able to resist the toxic effects of the pyrethrins or
carbaryls. How that resistance occurs, is stated as "...inhibiting mixed
function oxidases, synergists also potentiate mammalian toxicity."
What this means is that in addition to affecting the flea, these
synergists also keep our companions from being able to resist the
toxic effects. It is known that problems are more pronounced when the
product is applied to the animal's skin, rather than if the animal
ingests it while licking it from their hair .
A representative of the NAPCC stated to me that they had worked with
one company who was producing a pyrethrin flea spray which was causing
a lot of problems in cats. After the company reduced the percentage
of synergists to 1% there have been no additional reported problems
from their product.
So what's the answer? Always read the label of flea products keeping the
following figures in mind as a guideline.
Carbaryl 5.0% or less
Pyrethrins 0.15% or less
Synergists (see above) 1.0% or less
Precor (good) keeps insects from maturing
The first recommendation of the House Rabbit Society is to attempt to
remove fleas by using a totally non-toxic flea comb. If there aren't too
many fleas this may be a good solution (and it helps you to bond with your
rabbit). Because of the large volume of rabbits in my home which makes it
impossible for me to powder them all, and after speaking with one of my
veterinarians, I intend to use flea products (using the above guidelines)
on my rabbit's bedding and under their cage.
In conclusion, I'd say that it is advisable to try to get rid of the
fleas, and there are good safe powders on the market that will eliminate
the little pests. Powders are much safer than flea dips (we receive
numerous reports from veterinarians and owners, of flea dips killing
rabbits). Please, just pay attention and read the label before you
purchase a flea product.
These have all appeared within the last two years or so. The general
market seems to be heating up -- more demand or better research?
And the trend is definitely toward a substance on the coat or in
the bloodstream to kill fleas.
1 The Merck Veterinary Manual, seventh edition p.1665,1669,1501.
2 Snodgrass, H.L. J Toxicol Environ Health 1992 Feb. 35(2) P 91-105.
Specific recommendations from "Flea Control" for houses with pregnant
women or crawling infants are for a combination of microencapsulated
pyrethrins (eg Sectrol from 3M) and methoprene.
Since flea larvae can lay dormant for surprisingly long periods of
time, it is always possible for you and your pets to get fleas by
moving into a house or apartment in which the previous occupants had
- Advantage, from Bayer, is an adult flea poison. It
works by disrupting the flea's nervous system.
It is a liquid that you apply to the dog's skin and kills
on contact (therefore fleas are not required to bite the dog).
The substance will wash off, so swimming is recommended against.
is not absorbed into the bloodstream or internal organs. It is a
repellant and an insectide, and people are reporting being flea-free in
a matter of days.
Studies show that it is selectively
toxic to insects as other animals have receptors that do not bind
imidacloprid effectively and so are not affected. This is applied
along the dog's or cat's back and works for a month. After application,
watch your pet for signs of lethargy or allergic
reaction -- while studies show that there
are no adverse effects up to five time the recommended dosage, there are
always sensitive individuals.
Advantage runs $15-$20 for a dose
large enough for a labrador (two vials). Ingredients include:
imidacloprid -- a chloronicotinyl nitroguanidine synthesized from the
nitromethylene class of compounds. This binds the insect's nicotinyl
receptor sites thus disrupting normal nerve transmission and causing
- Similar to Advantage, but is not water soluble (must use alcohol to
wash it off). It can be used on pups, kittens, cats, and dogs.
It does not use pyrethrins/permethrins (good news for dogs allergic to
these substances). It can repell for up to three months (in infested areas,
the reported efficacy is closer to a month). Active ingredient is
fipronil 5-amino -1- (2, 6-dichloro-4 [trifluoromethyl]phenyl) -4-
(1,R,S)- (trifluoromethyl0sulfinyl) -1H-pryazole-3-carbonitrile 0.29%
inert ingredients 99.71%.
Fipronil is a nervous transmission interruptor, causing rapid death to
fleas and ticks. Kills 96% of fleas in the first two hours, 100% within
24 hours. Ticks die before attachment. Fipronil is from the new
phenylpyrazole class. Unlike any other molecule, fipronil acts on the
GABA (gamma aminobutyric acid) mediated chloride channels of invertebrates.
It is not systemic, it collects in the sebaceous glands (so you aren't
supposed to give a bath 2 days prior or after, so there is oil on the
skin for it to attach to).
It can be used on puppies (8 weeks or older) and kittens.
It has a toxicity rating of LD 50 which is similar to aspirin.
Frontline CAN BE TAKEN OFF with Sulf Oxydex Dog and Cat shampoo,
DVM Pharm. The peroxide in the shampoo deep cleans the sebaceous glands
and therefore washes all Frontline away when rinsed.
- Works like Frontline, but is only approved for dogs. Contains
permethrins, and is supposed to repell both fleas and ticks.
Active ingredients: Pyriproxyfen: 21[1-methyl-2-(phenoxyphenoxy)ethyoxy]
inert ingredients 97.95%
Also has NYLAR, which is an insect growth regulator.
- ProTICal (formerly Defend)
- A topical agent, the product is absorbed into
the skin and spread through the fat layer; some dogs are sensitive to
this. Not approved for cats. Supposed to work for both fleas and
ticks, but many reports of tick infestations anyway. Active ingredient
- Proban (cythioate) and Prospot (Fenthion)
- These are not licensed for use in
cats in the U.S. They may be used on dogs. They work on the
principle that if you poison the bloodstream, the fleas will die after
ingesting the poisoned blood. Several problems: first, you *are*
introducing a low level of poison into your pet's bloodstream, and the
long-term effects are unknown. Second, this does not help at all the
pet that is allergic to fleas and cannot afford to be bitten in the
- Program (lufenuron)
From Steve Dudley:
Ciba-Geigy Animal Health has pioneered an approach to flea control
with the systemic use of an
insect growth regulator
phenyl urea lufenuron. This IGR acts as a chitin synthesis inhibitor
causing mortality in hatching flea eggs and moulting larvae. Hatching
fleas are unable to get out of the egg shell because the egg tooth, a
chitin structure, cannot form. Larvae die during moults, again due to
the inhibition of chitin formation. The IGR has no adulticidal activity,
but female fleas that ingest the compound transfer it to the ovaries and
eggs (transovarial effect).
Chitin is a polysaccharide, that along with various structural proteins
makes up 25-50% of the dry weight of insect exoskeletons. It is
necessary for integrity and strength.
Lufenuron, marketed in the US
under the PROGRAM tradename (available by veterinary prescription
only), and widely available in Europe, is administered
orally with food, in tablet form, for dogs. A suspension form is administered
to cats. To maintain effective levels of control for a 30 day period,
10mg of lufenuron per kg of body weight is recommended for dogs. For
cats, 30mg of lufenuron per kg of body weight is recommended. Dosages
are absorbed from the intestinal tract into the general circulation and
retained in adipose tissues. Excess is excreted. From the adipose
tissue, lufenuron is slowly released back into the general circulation
and excreted over time. The major route of elimination is via the feces.
It was found that after two days of feeding on treated dogs, no adult fleas
developed from eggs laid by females feeding on the dogs. 80% control of
a flea population takes about 4.5 weeks, as pre treatment flea larvae and
pupae in the environment still must complete their life cycles. Acute,
sub chronic, and chronic dose studies revealed no adverse affects
relative to the animals safety and tolerability. Used in conjunction
with flea adulticides, no enhanced signs of toxicity were evident.
This was taken from the following article: A Novel Approach to Flea Control:
Systemic Use of Lufenuron. By Rudolf Schenker and Philip A. Lowndes. Ciby-
Geigy Ltd., Basel, Switzerland.
Other notes: a version approved for cats (liquid form) is out now. It's
also approved for use with nursing mothers.
This is not toxic to adult fleas.
Program has no warnings or contraindications on the FDA approved
package insert; it can be used in conjunction with other
flea control products and heartworm preventives.
The main drawbacks of
this regime is that it is a preventive type of remedy; it will not work
well (or immediately) against an acute flea population. It also
requires that the dog be bit by all the fleas in the house for them to
produce the defective larvae; this is not acceptable when the pet in
question has flea allergies! Finally, for Program to be effective,
all animals in the house need to be placed on it.
- Topical application, kills fleas, eggs, and ticks. Repels
mosquitos. Works for one month. Sometimes turns white hair yellow
temporarily. Contains permethrins and IGR. Contraindicated for use in
If this may be the case, you can prevent the potential problem by
spraying or treating the place *before* you move in, if at all
possible. For example, if the place has been uninhabited long enough
that all the adult fleas are dead, methoprene should be sufficient,
otherwise use sprays that will also work on the adults.
In general, you will have to use a combination of some of the
approaches above. You will also want to launder any bedding and other
launderable items to rid them of fleas at the same time. If you comb
your pet regularly, you will be able to spot an incipient increase of
fleas and make pre-emptive strikes. If you have a bad flea problem,
getting your carpet professionally cleaned in addition to other
control methods will help in removing potential food sources for the
People have asked me what my personal methods are. I prefer to use a
IGR type of spray. I obtain Vigren (methoprene) from Gardens
Alive! and spray my house every four months and
also after I have the carpets cleaned. Since I show my dogs
(hence exposing them to flea-infested sites), I will take some
preventive action before going by spraying them with
Ovitrol Plus by VetKem which is
a mixture of microencapsulated pyrethrins and methoprene and seems to
last a long time, several weeks if they don't go swimming. I have not
had a serious problem with fleas for several years, despite living in
Southern California. I have also used Borax in the carpet to good
effect, but have become concerned about possible inhalant problems and
damage to the carpet. Since one of my dogs and my cat have flea
allergies, I have not tried out the Program product, nor do I intend to,
though I've heard plenty of wonderful things about it.
Ticks are in the phylum of animals called Arthropoda (jointed
appendage). This phylum of animals is the largest in the animal
kingdom. There are over 850 different species of ticks, and they
parasitize every class of terrestrial vertebrate animal, including
Ticks are small rounded arachnids that cling to one spot and do not
move. They have inserted their head under the skin and are engorging
themselves on the blood. Diseases carried by ticks means that you
should have yourself or your pets checked after you find ticks. On
the one hand, ticks are a little easier to deal with since they remain
outdoors, and do not infest houses the way fleas do; on the other
hand, they carry more dangerous diseases and are harder to find.
Ticks are the most important arthropod in transmitting diseases to
domestic animals and run a close second to mosquitoes in arthropod
borne human diseases. They transmit a greater variety of infectious
agents than any other type of arthropod. Ticks can cause disease and
illness directly. They are responsible for anemia due to blood loss,
dermatosis due to salivary secretions, and ascending tick paralysis
due to neurotoxins in the salivary secretions. They also can be the
vector of other diseases. Some of the more noted
are babesiosis, anaplasmosis, ehrlichia,
East Coast fever, relapsing fever, rocky
mountain spotted fever and, of course,
There are two basic types of ticks. Soft ticks, the argasids, are
distinguished by their soft, leathery cuticle and lack of scutum.
They can be recognized easily by their subterminal mouthparts that are
on the underside of the tick. Soft ticks when engorged with blood
blow up like a balloon. Soft ticks are fast feeders, being able to
tank up in a matter of hours.
Hard ticks, the Ixodids, have a hard plate on the dorsal surface and
have terminal mouthparts. When attaching, a tick will slice open the
skin with the mouthparts and then attach itself. They also secrete a
cement that hardens and holds the tick onto the host. Hard ticks are
slow feeders, taking several days to finish their bloodmeal.
During feeding a tick may extract up to 8 ml of blood, they can take
100X their body weight in blood. Interestingly, they concentrate the
blood during feeding and will return much of the water to the host
while losing some by transpiration through the cuticle.
All ticks have four life cycle stages. Adult ticks, produce eggs. A
female tick can produce up to 20,000 eggs. Mating usually occurs on a
host, after which the female must have a blood meal in order for the
eggs to develop. Ixodid ticks are unusual in that mating does not
occur on the host. The eggs are laid in the soil or leaf litter after
the female drops off the host. These eggs hatch into a stage known as
the larva. The larva is the smallest stage and can be recognized by
having only 3 pairs of legs. These "seed ticks" are produced in great
numbers. They must find a host and take a blood meal in order to molt
to the next stage called the nymph. If the nymph can feed on a host,
it will develop into the adult tick.
Ticks vary greatly in how long this cycle takes and the number of
hosts involved. Some ticks are one host ticks; the entire cycle
occurs on that one host. Others use two hosts, some three and some of
the soft ticks are multi-host ticks.
Ticks require high humidity and moderate temperature. Juvenile ticks
usually live in the soil or at ground level. They will then climb up
onto a blade of grass or the leaf of a plant to await a potential
host. They will sense the presence of a host and begin the questing
behavior, standing up and waving their front legs. They are able to
sense a vibration, a shadow, a change in CO2 level, or temperature
change. When unsuccessful in their "quest" they become dehydrated and
will climb back down the plant to the ground to become rehydrated.
Then back up the plant, etc., until they are successful or they die.
Some ticks have been known to live for over 20 years and they can live
for a very long time without food. Their favored habitat is old
field-forest ecozone. One way to cut down the number of ticks is to
keep the area mowed.
When you find a tick, use tweezers to pick up the body and pull
s-l-o-w-l-y and gently, and the mouthparts will release. You should
see a small crator in your dog's skin, if you see what looks like
black lines, you've left the head of the tick in. At this point, if
your dog is mellow enough, you should try and pick it out. Otherwise,
you may need to take your pet into the vet, as the head parts will
lead to an infection. Ticks carry a lot of rickettsial diseases,
including Lyme disease and Rocky Mountain Spotted Fever, so you should
wash your hands thoroughly with soap after handling a tick.
Some veterinarians will put on gloves, smear one finger with a bit
of mineral oil and massage the protruding part of the tick for a
minute or so. The tick will back out.
Lyme disease (see below) is usually carried by tiny deer ticks (two
other kinds of ticks have also been identified as carriers) , which
are the size of the head of a pin. You must look yourself or your pet
over very carefully to find these kind of ticks. Other ticks can be
as large as peppercorns. This can vary depending on whether or not
the tick has yet engorged itself -- the deer tick can be as large as
the more familiar Dog Tick if it has had time to feed. So if you are
in doubt, preserve the tick in rubbing alcohol and have your vet take
a look at it.
If you have left the head of the tick in your pet's skin, chances are
there will be an infection or an abscess in a week or so. Try
disinfecting the area thoroughly with 70% alcohol (it takes about 5
minutes for alcohol to sterilize an area). Ethyl alcohol is less
toxic than rubbing alcohol; vodka or any high-proof liquor will work, but
good commercial antiseptic cleansers are recommended.
Then apply a combination
antibiotic ointment. If an infection occurs anyway, take your pet in
to the vet to have it drained.
To dispose of the tick, drop it into alcohol to kill it, then dispose
of it. Flushing them down the toilet WILL NOT KILL THEM. Squishing
them with a thumbnail is not recommended, and is not easy anyway. You
might save the tick in a jar of alcohol for identification, to help
decide whether possible infection has occurred.
Adult ticks can remain on deer and other mammals through the fall
and winter. If you spend a lot of time outdoors during this period,
be sure to check yourself, your family and your pets daily for ticks.
If you hunt or trap, check areas where you cache your game for ticks
that may have fallen off during handling.
- Don't use any of the folklore remedies (matches, cigarettes, pins,
gasoline) that will irritate the tick. They increase the
likelihood that the tick will "spit up" in you, which increases
the risk of disease.
- Oil is not effective because the breathing requirements of the
tick are so small it could last hours covered with oil.
- The mouthpiece is barbed rather than spiralled, so trying to
rotate the tick out doesn't provide any advantage.
- The preferred method is to use special tweezers designed for that
purpose, and pull straight out.
A helpful practice is to wear long pants tucked into white socks; this
way they crawl up the *outside* of your pants and you can spot them in
the field. Also wear a hat: they can drop from trees onto your head.
Ticks like long grass on the edges of woods (especially deer ticks)
They crawl up onto the grass blades and cling to you as you walk past.
If you comb your pet with a wide tooth flea comb right after taking a
walk, chances are you will find unattached ticks crawling around.
Ticks don't attach themselves right away: they look around for good
real estate. It's much easier to remove ticks before they attach, and
easier to remove newly attached ticks than ones that have been feeding
for a while.
If you have heavy infestations of ticks in your area, spraying your
backyard against ticks may be a good idea, especially if your pet is
If you have a dog, a new product called Preventic appears to be highly
effective. It is a tick collar that kills ticks shortly after they
attach to your dog. The active agent is Amitraz, which prevents
attachment and kills but does not affect fleas. Amitraz is not an
insecticide (flea killer) but an "arachnicide" (8-legged bug killer -
ticks and spiders are in the same class.)
The collar works best if it is kept dry. Rain is OK, but swimming is
out as exposure to water reduces its effectiveness. Removing the
collar is apparently non-trivial. You don't need a prescription,
although the only place you might find it is at the vet's or in a
Twenty-four hours after putting it on, your dog is protected from
ticks. Many people have written about how effective it was for their
dog. It is NOT recommended for cats, however, and some dogs appear to
have individual sensitivity to it. If your dog becomes lethargic or
irritable, remove the collar. NOTE THAT THE COLLAR IS TOXIC -- if your
pet eats any part of the Preventic collar, take him in to the vet
immediately. Symptoms include vomiting, white gums and unsteadiness. There is an
antidote for it, called Yobine.
There is a product, called Tiguvon (chemical composition) that is a
systemic, administered monthly. Its drawbacks seem to be that it is
expensive and that the tick needs to fully engorge itself to be
poisoned by the systemic.
Ticks don't typically infest houses, unless you have a pet that had an
overlooked tick that dropped off and hatched its eggs. In the
Northeast US and other temperate climates the tick Rhipicephalus
sanguineus is almost exclusively limited to domestic habitats,
particularly kennels. Becasue the entire life cycle occurs inside,
control strategies become similar to that of controlling fleas. You
will have to spray your house in this case as ticks hatch an
unbelievable number of eggs. Your local hardware store can give you
tips on what is best to spray with. You are not too likely to find
"natural" or low-toxic sprays for ticks. On the other hand, one
spraying is likely all you need to clear them out of your house. They
are not tenacious the way fleas are.
Common recommendations for reducing ticks in your backyard are to keep
the weeds or grass well-mowed. There are commercial sprays effective
against ticks. If you live in tick-infested areas, always examine
your dog (and yourself!) after being outside. Control vermin around
your house and discourage deer and other wild or feral animals from
your property, as they are often vectors for ticks (as well as a slew
of other nasties).
is a complex illness that affects wild and domestic
animals, including dogs, as well as humans. It is caused by a
corkscrew-shaped bacterium called borrelia burgdoferi.
First noted in 1977, the disease has rapidly spread throughout the
contintental US and Canada. Studies have shown that migrating birds
have helped disperse infected ticks to new areas. Hunting dogs, or
any dog that runs in tick-infested fields, can bring the problem home
with them. And so do people who move from place to place with
infected pets. It is expected that Lyme disease will soon be a
problem in all 48 contiguous US states.
You should note that Lyme disease is fairly easily treatable with
antibiotics. Problems occur when it is left untreated. Lyme disease
appears to affect humans a bit differently and is more complex to
Sources for additional information on Lyme disease:
When a tick bites, the bacterium is transferred into the blood of the
host. The deer tick (Ixodes dammini) is found in the Northeast and
upper Midwest; the black-legged tick (I. scapularis) is found in the
Midwest and Southeast; and the Western black-legged tick (I.
pacificus) is found mainly in the coastal areas of California, Oregon,
and Washington. Hosts include deer, migratory birds, rabbits, mice,
raccoons and skunks ... plus dogs, cats, cattle, horses and humans.
- State and local health departments
- Your veterinarian or family physician
- Local Lyme Disease support and informational groups can be found
in many areas
- Lyme Disease Foundation, Inc.
P.O. Box 462
Tolland, Connecticut 06084
- The Lyme Disease Electronic Mail Network publishes the "
Newsletter" once every 10-15 days. The Newsletter contains
timely news about the Lyme disease epidemic. Medical abstracts,
treatment protocols, prevention information, and political
happenings are all included. In addition, subscribers may ask
questions to the patients, doctors and researchers on the net.
To subscribe, send email to listserv@Lehigh.EDU, with
in the body of the message. Problem reports only should be sent
to Marc Gabriel (email@example.com), the owner of the list.
Besides tick bites, Lyme disease may be spread by contact with
infected body fluids. Studies indicate that transmission may occur in
this manner from dog to dog, and possibly from cow to cow and horse to
horse. Transmission from animal to human *may* be possible. In utero
transmission has been observed. Animals may be reinfected with Lyme
The major vector for the deer tick is the mouse; deer have relatively
little to do with it. Deer simply act as a home for the overwintering
adults. Removing deer from an area has little long term effect on the
tick population since the adults simply find another animal to act as
a winter host.
The symptoms of this illness have now been separated into three
stages. If caught before the end of the first stage, the illness is
usually easily treated by antibiotics.
In general, a high fever combined with stiffness or arthritic symptoms
(in both people and animals) can indicate Lyme disease.
The next two stages represent greater systematic involvement and
include the nervous system and the heart. If still untreated, the
third stage involves the musculoskeletal system.
The erythema migrans (small round rash at the site of the bite) is the
best early sign of a problem. Unfortunately, the tick that bites is
usually a larva or nymph and so is seldom seen. The resulting rash is
seen in approximately 80% of adults but only about 50% of children.
It is imperative that it be diagnosed early since the more severe
symptoms can begin quickly.
Treatment consists of several broad spectrum antibiotics -- including
tetracycline, penicillin, and erythromycin. This is effective,
especially in the early stages. Consult with your veterinarian or
There is a vaccination against Lyme disease for dogs that is now
available. It is Borrelia Burgdoferi Bacterin (Fort Dodge
Laboratories). It is supposed to have a duration of immunity that
lasts through the tick season. One for people is coming out now as
An interesting discussion of what is happening in the veterinary
community with regard to Lyme disease is summarized in an easy-to-read
letter titled "Questions 'push' for vaccinations against Borrelia
burgdoreri infection," in the Journal of the American Veterinary
Association, 201(10), 11/15/92.
They can carry various diseases including the protozoa Babesia canis
and the rickettsia Ehrlichia canis, both of which can cause serious
illness in dogs if untreated.
Also unlike most other ticks R. sanguineus can cause *in house*
infestations - that is, like fleas you can have full life cycles
occuring in the privacy of your very own home. In house infestations
of R. sanguineus in the northeast is apparently not that uncommon in
Consumer Reports, August 1991.
Contains an article discussing flea collars: brands and effectiveness.
Klein, Hilary Dole and Adrian M. Wenner. Tiny Game Hunting. Bantam,
1991. ISBN 0-553-35331-4.
A good reference on how to get rid of fleas.
Melman, Steven A. and Karen L. Campbell, "Flea Control" (Chapter 9 in
Natural Garden Research Center
Hwy 48 - PO Box 149
Sunman, IN 47041
Fleas and Ticks FAQ