Tempting as it may be to simplistically consider fleas as horrible insects, the bane of dogs everywhere, poisoning your dog in a vain attempt to wipe fleas out of existence doesn’t really make sense. Even though more than half a billion dollars annually are spent on products that kill fleas in that vain pursuit.

1. CONS U M ER ALERT
Are “Spot-On” Flea Killers Safe?
Absolutely not, says our author, despite what the commercials say.
BY KATHLEEN DUDLEY
T
empting as it may be to simplistically
consider fleas as horrible insects, the
bane of dogs everywhere, poisoning
your dog in a vain attempt to wipe
fleas out of existence doesn’t really
make sense. Even though more than half a
billion dollars annually are spent on prod-
ucts that kill fleas in that vain pursuit.
Of course fleas can make dogs (and
everyone else in the household) perfectly
miserable. But it’s not as if using toxic flea-
killing chemicals is the only way to control
fleas. When we attempt to get rid of our
dogs’ fleas by utilizing chemicals that are are
“Spot-on” flea-killers are
toxic to the brain and nervous system, that effective, but the long-term
effective, long-term
effects
effects of their constant use is
may disrupt hormone (endocrine) systems, effect,
unknown. In ef fect, our dogs
and that cause cancer, it’s sort of like burning are
are test subjects that will
the house down to get rid of ants – effective, determine safety.
determine their safety.
sure, but what are you left with?
In the next issue of WDJ, we will powders, sprays, shampoos, and dips exposed. We cannot make informed indi-
describe effective, nontoxic methods of flea containing organophosphates (chlorpyrifos, vidual decisions on the acceptability of those
control. No dogs (or any other members of malathion, diazinon), pyrethrins, synthetic exposures, a basic element in the mainte-
the household) will get sick from these pyrethroids, and carbamates, were the nance and protection of our own health.”
methods, and no dogs (or any other members cutting-edge solutions to our flea problems. Spitzer adds, “The requirements for market-
of the household) will die from them. In They were effective, but unfortunately, they ing a new product fall considerably short of
contrast, dogs do get sick and die from the also caused disease and sometimes death. providing safety for our animal and human
toxic chemicals we will describe in this Given enough time, most pesticides families.”
article. eventually cause enough human and animal
injuries that they are identified as hazards Active and inert ingredients
New products not safer and are removed from the market. To fully understand the risks associated with
All pesticides pose some degree of health While the newest flea products – so- any of these products, it is important to un-
risk to humans and animals. Despite adver- called “spot-on” liquids that are applied derstand the various components in a flea
tising claims to the contrary, both over-the- monthly to a dog’s skin – are being marketed product, or any chemical product that you
counter and veterinarian-prescribed flea- aggressively by the manufacturers and may buy, for that matter.
killing topical treatments are pesticides that veterinarians and represented as safe Like other chemical products, all flea
enter our dogs’ internal organs (livers, kid- alternatives to their predecessors, the fact products are made up of “active” and “inert”
neys), move into their intestinal tracts, and is, they are simply newer. All the “active” ingredients; strangely, the actual definitions
are eventually eliminated in their feces and ingredients in these spot-on preparations – of those phrases are very different from what
urine. Not only that, but the humans and imidacloprid, fipronil, permethrin, they seem to connote. In the case of flea-
other household animals who closely inter- methoprene, and pyriproxyfen – have been killing chemicals, the “active” ingredient
act with dogs who have been treated with linked to serious health effects in laboratory does, in fact, target and kill fleas – but some
these chemicals can be affected by the tox- animals (see chart, page 20). of the “inert” ingredients are poisons, too.
ins. What happens to the health of all ex- “The public must recognize that any de- While the word “inert” suggests benign
posed individuals during this systemic ab- cision to use a pesticide, or to otherwise be activity and even connotes safety in the
sorption and filtration process varies from exposed to pesticides, is a decision made in minds of many consumers, legally, it simply
animal to animal, but the laboratory and field ignorance,” says Eliot Spitzer, Attorney means added substances that are not the
trial results clearly indicate toxicity on the General of the New York Environmental registered “active” ingredient. This is
chronic and acute levels. Protection Bureau. “We do not know the important because most people assume that
Until recently, foggers, flea collars, identity of the chemicals to which we are only the “active” ingredient in a chemical
18 | FEBRUARY 2002 Copyright© 2002, Belvoir Publications, Inc. TO SUBSCRIBE, CALL (800) 829-9165

2. product is of concern. Many people feel Why don’t pesticide manufacturers have cent of a test population – and to determine
comforted by the idea that a product contains to disclose all the ingredients in their prod- the acute and chronic effects. Throughout
only a minuscule amount of an “active” ucts? This kettle began brewing in 1949, and following the test, subjects are killed in
ingredient and up to 99.9 percent “inert” when the U.S. Congress passed the Federal order to study the specific system damage
ingredients – a typical formula in many Insecticide, Fungicide, and Rodenticide Act (lungs, kidney, etc.). Acute disease tests,
pesticide products. Actually, this makeup (FIFRA), allowing manufacturers confiden- such as nervous system and skin reactions,
should frighten consumers. tiality on issues they claimed would other- can be performed over a relatively short time
Why? Because the Environmental Pro- wise make them vulnerable to market com- period. Most studies are conducted for 3-,
tection Agency (EPA, the government petition. “Inert” ingredients, in other words, 13-, or 52-week intervals, and use exagger-
agency that oversees the pesticide industry) became protected by industry as “trade se- ated dosages to compensate for the short
requires a higher (if not high enough) stan- crets.” While protecting industry, this act testing periods.
dard of scrutiny for “active” ingredients; supersedes the public’s right to know to what “Because of the short period under which
these must undergo a battery of tests to de- we are being exposed and the health haz- the studies are conducted, the health effects
termine their toxicological profiles, be reg- ards resulting from these exposures. And resulting from the higher doses of the chemi-
istered with the EPA, and be listed on the without full disclosure, we are unable to cals are relevant,” says Dr. Virginia Dobozy
product inserts and packaging. In contrast, make educated decisions as to which chemi- of the EPA’s Pesticide Division. These ef-
“inert” ingredients need not be listed on the cals we want to avoid. fects can include head-nodding; facial
product inserts and packaging and are sub- twitching; exaggerated blinking; gag re-
ject to much less testing than the “active” Laboratory studies sponses; weight increase of the spleen, thy-
ingredients; “inerts” are generally tested in Obviously, products undergo testing in or- mus, and adrenal glands; and/or atrophy of
short-term studies for acute toxicity only. der to qualify for EPA registration, and pre- the thymus.
The word “inert” implies chemicals that sumably, most of the overt dangers a prod- Long-term studies, needed to understand
are somehow inactive. In actuality, many uct can exert are ameliorated before the the chronic effects of the pesticides, are few
“inert” ingredients used in pesticides are product can be marketed. Scientists use by comparison. Chronic disease such as can-
as toxic, or more toxic, than the registered healthy, adult, genetically identical mam- cer, immune suppression, developmental or
“active” ingredients. For example, naphtha- mals to test pesticides, and then extrapolate reproductive damage, and DNA damage can
lene, one of the “inerts” in an imidacloprid health information regarding the safety of take months or years to manifest.
product, showed clear evidence of cancer the product to domestic animals and human However, the cumulative effect –
activity through inhalation (nasal cancers), beings. In the case of flea products, the labo- potential damage from continued use of one
as well as anemia, liver damage, cataracts, ratory tests are performed on live mice, rats, specific pesticide product or multiple
and skin allergies. An unidentified “inert” cats, and dogs. products over a dog’s lifetime – is unknown.
ingredient in the flea product Advantage was These toxicological (poison) studies are Also unknown is the potential for synergistic
implicated in the death of kittens who re- performed to establish the LD 50 – the oral effects – combined impacts of chemical
ceived doses within laboratory tolerances. dose at which the product would kill 50 per- exposures from their home and outdoor
environments. Neither the cumulative nor
the synergistic effects of chemicals in
Spot-On Pesticides and Their Ingredients products are required to be tested by the EPA
before a product is made commercially
Advantage Frontline Top Spot available. So, our dogs may be more
Bayer Corporation, Shawness Mission, KS Merial Limited, Iselin, NJ vulnerable to unknown chemical-related
(800) 255-6826 or nofleas.com (800) 660-1842 or frontline.com dangers than the happy commercials would
Active ingred: 9.1% imidacloprid Active ingred: 9.7% fipronil have you believe.
Inert ingred: 90.9% (not disclosed) Inert ingred: 90.3% (not disclosed) Critics of the pesticide industry claim
(MSDS indicate inerts include some solvents) (MSDS indicates inerts include ethanol that the EPA registers pesticides not on
7.7%, polyvinlpyrrolidone 6.9%,
Adams Spot-on Flea & Tick Control safety, but on a cost-benefit basis, balanc-
butylhydroxytoluene 0.3%,
Farnam Pet Products, Phoenix, AZ butlyhydroxanisole 0.3%, and carbitol ing health and environmental concerns
(602) 285-1660 or farnam.com [diethylene glycol monoethyl ether]) against the economic gain to the manufac-
Active ingred: 45.0% permethrin (Note: Frontline Plus is essentially the same turer and the end user of the product. But
Inert ingred: 55.0% (not disclosed) as Frontline Top Spot, but with the addition even if the pesticide manufacturers and the
of 8.8% methoprene, an IGR.) EPA are not overly concerned about our
BioSpot Flea & Tick Control
Farnam Pet Products, Phoenix, AZ safety, we as consumers and guardians
Zodiac FleaTrol Spot On
(602) 285-1660 or farnam.com should be very concerned.
Wellmark International, Schaumburg, IL
Active ingred: 45.0% permethrin (800) 950-4783 or zodiacpet.com
5.0% pyriproxyfen Active ingred: 45.0% permethrin Too good to be true
Inert ingred: 50.0% (not disclosed) 3.0% methoprene (IGR) Today, spot-on flea preparations are consid-
Inert ingred: 52.0% (not disclosed) ered by many as the Rolls Royce of flea
Defend EXspot Treatment
Schering-Plough Animal Health, Union, NJ products, and sell swiftly in veterinary clin-
(800) 842-3532 or www.sgp.com/main.html ics and pet stores. Each of the makers of
Active ingred: 65.0% permethrin these products claim that they are safe – safer
Inert ingred: 35.0% (not disclosed) than ever – and that only the targeted in-
sects will be affected by the products’ neu-
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3. Adverse Effects of Ingredients Found in Spot-On Products
INGREDIENT TYPE AFFECTED SYSTEM LABORATORY ANIMAL HEALTH EFFECTS
Fipronil Active Carcinogen Thyroid cancer (possible human carcinogen)
Organ damage Increased organ weights, altered thyroid hormones
Neurotoxin Loss of appetite, underactivity, convulsions, whining, barking, crying
(nervous system (vocalization), body twitches/tremors, overactivity, salivation, stiffened limbs,
damage) unsteady gait, incoordination, labored breathing
Teratogen Reduced fertility, decreased litter size and body weights in litters, fetus mortality
(reproductive damage)
Skin problems Severe moist inflammation, ulcerations, skin sloughing, chemical burn, itching,
hair loss at and beyond the application site
Imidacloprid Active Carcinogen Yet to be determined; evidence of thyroid lesions in dogs
Organ damage Liver, kidney, thyroid, heart, lungs, spleen, adrenal, brain, gonads; liver toxicity,
increased organ weights, thyroid lesions, increased cholesterol levels in dogs
Neurotoxin Incoordination and labored breathing, muscle weakness including muscles
necessary for breathing
Teratogen Increased miscarriages and smaller offspring
Methoprene Active Organ damage Liver enlargement
Neurotoxin Headaches, eye and throat irritation, difficulty breathing, confusion, dizziness
and nausea in humans
Permethrin Active Carcinogen Liver and lung tumors (possible human carcinogen)
Organ damage Kidney enlargement, changes in lung
Neurotoxin Tremors, incoordination, elevated body temperature, increased aggressive
behavior, learning disruption
Teratogen Fertility is affected
Autoimmune Bone marrow changes in laboratory animals
Pyriproxyfen Active Teratogen Reduced weight gain, toxicity to pups
Ethanol Inert Teratogen Adverse effects on fetus
Butylhydroxanisole Inert Carcinogen Animal carcinogen (possible human carcinogen)
Butyldydroxytoluene Inert Carcinogen Animal carcinogen (possible human carcinogen)
Carbitol Inert Neurotoxin Headache, depression, nausea, vomiting, diarrhea, abdominal and lumbar pain
Organ damage Pathological lesions in brain, lungs, liver menni; possibility of pulmonary edema,
intravascular hemolysis and bone marrow depression
Polyvinlpyrrolidone Inert Carcinogen Not evaluated by EPA for carcinogenic
Sources of the above information include reports from the Environmental Protection Agency; Occupational Safety & Health Administration, US Dept. of Labor; Extoxnet:
Extension Toxicology Network; Journal of Pesticide Reform, Material Safety Data Sheets, Pesticide Action Network North America, and more.
rotoxic impacts. The products are frequently pyrethroid insecticide) – all work by disrupt- tion, labored breathing, thyroid lesions, re-
advertised as safe for small children and ing the nervous system of insects, killing by duced birth weights, and increased fre-
adults as well as puppies (over eight weeks) contact or ingestion. The fourth type con- quency of birth defects.
and geriatric dogs. Do they sound too good tains insect growth regulators (IGR), which Fipronil was introduced in the United
to be true? Well, perhaps they are. don’t kill, but interrupt the flea’s life cycle. States in 1996. It is a neurotoxin and sus-
The spot-on flea products fall into four Imidacloprid is the first of its class of pected human carcinogen. Fipronil can
general categories of insecticides. All have insecticides, and is relatively new on the cause liver toxicity, thyroid lesions (cancer),
neurotoxic effects. The first three – block; it was introduced in 1994. Labora- damage to the kidneys, increased cholesterol
imidacloprid (a chloro-nicotinyl insecti- tory testing on mice, dogs, and rats, indi- levels, alterations in thyroid hormones, in-
cide), fipronil (a phenylprazole insecticide), cates that this insecticide can be neurotoxic coordination, labored breathing, increased
and permethrin (a synthetic broad spectrum to laboratory animals, causing incoordina- miscarriages, and smaller offspring.
20 | FEBRUARY 2002 Copyright© 2002, Belvoir Publications, Inc. TO SUBSCRIBE, CALL (800) 829-9165

4. could smell it on their breath in a matter of
Learning to Read the Label minutes following the application.” Blake
Don’t
Don’ t just “consult your stated that this indication of immediate ab-
are
Note that cats ar e at a special risk We
veterinarian.” We would
product,
of being poisoned by this product, suggest NEVER using on sorption did not tally with what he had been
even if they simply have “close “debilitated, aged, medicated, led to believe by reading Bayer’s literature.
physical contact” with tr eated pregnant
pr egnant or nursing” dogs. He continues to question its safety for his
dogs.
EPA Wor
ord”
US EPA “Signal Word” clients’ animals.
Neurological health effects
Logic tells us that a topical chemical that is
not absorbed into the skin has no chance of
causing neurotoxic effects. Then why do the
Material Data Safety Sheets (MSDSs) for
all the permethrin-containing pesticides rec-
ommend preventing their products from hav-
ing prolonged contact with the skin? And
why do they all state that skin sensations,
such as “numbness and tingling,” can oc-
cur? Schering-Plough’s MSDS makes an ad-
product maker.
This is the product maker. ditional statement about its Defend EXspot
List of “active” Treatment: “can be harmful if absorbed
problems
If your dog displays any pr oblems (known) and “inert”
“inert”
repor
eport
following application, r eport this to resear
esearching
When researching (who knows what?) through the skin and harmful following in-
maker. manufacturers
the maker. Pesticide manufacturers a chemical, use ingredients.
ingredients. halation,” causing headaches, dizziness, and
are r equired by federal law to
are requir
equired EPA
the EPA nausea.
forwar repor
ward eports product
forward reports of pr oduct injuries Registered
Register ed
EPA.
to the EPA. Number.
Number. Bayer does not reveal more than 90 per-
cent of the ingredients in Advantage, but its
MSDS does warn us to “use a respirator for
In a review of the fipronil pet formula- companies’ literature describes in vague and organic vapors” in order to avoid “respira-
tions, Dr. Virginia Dobozy of the EPA’s Pes- contradictory detail how the chemicals don’t tory tract irritation and other symptoms such
ticide Division states that “this is a persis- go beyond the hair follicles and fat layers of as headache or dizziness” (symptoms of
tent chemical that has the potential for ner- the dogs’ skin. nervous system exposure). Bayer’s promo-
vous system and thyroid toxicity after long Take, for example, information pub- tional literature for Advantage, however,
term exposure at low dosages.” lished on Merial’s Web site for Frontline states that “studies prove that using 20-24
Permethrin, a synthetic broad spectrum (“How Frontline Works”). In one place, it times the dosage on dogs and cats does not
pyrethroid insecticide, is suspected to be an clearly states that fipronil (Frontline’s “ac- cause any internal or external side effects,”
endocrine disrupter and a carcinogenic in- tive” ingredient) is absorbed into the skin and that “. . . switching to Advantage from
secticide (causing lung cancer and liver tu- (“Sebaceous glands pro- another flea control product poses virtually
mors in laboratory animals). Some vide a natural reservoir no risk to your pet.”
permethrin products have additional “ac- for Frontline . . .”), but Dr. Graham Hines, a veterinarian from
tive” ingredients in lesser percentages, and other statements suggest the United Kingdom, treated a four-year-old
include methoprene, and pyriproxyfen (de- that fipronil stays there female German Shepherd who had two Ad-
scribed below). and then leaves through vantage Top Spot treatments. He reported
Methoprene and pyriproxyfen are both the same entry point with- that “both times she became unusually
insect growth regulators (IGR), which limit out moving into any other clingy, and would not leave her guardian’s
the development of juvenile fleas so they parts of the dog’s body – an illogical con- side, yet paced up and down all day, very
cannot reproduce. Test results indicate that clusion. restlessly. These symptoms persisted for 48
methoprene causes enlarged livers and de- When the EPA’s Dr. Dobozy reviewed hours before a gradual return to her normal
generation of parts of the kidneys. the results of a fipronil metabolism study, state.” The neurotoxic effects were clear to
All of the above active ingredients have she reported that “significant amounts of ra- Dr. Hines.
induced responses in laboratory animals that dio-labeled fipronil were found [not only] Dr. Blake also finds different results than
give cause for alarm. While these new prod- in various organs and fat . . . [but they were the Bayer literature. “We are told that the
ucts are suggested as safer than their prede- also] excreted in the urine and feces, and product affects only insects’ nervous sys-
cessors, they indicate high levels of acute were present in other parts of the body . . . tems, not mammals’. Several of my clients
and chronic poisoning from short-term use. which demonstrated that the chemical is told me that they accidentally got some
absorbed systemically.” Advantage on their hands and when they
Method of action Veterinarians and pet owners who pay touched their mouths, their lips became im-
Whether or not it is purposeful, manufac- close attention can witness evidence that mediately numb for several hours. So much
turers of these spot-on flea products have these products are indeed systemically ab- for not having an effect on the nervous sys-
managed to convince many veterinarians sorbed. Dr. Stephen Blake, a San Diego vet- tem of mammals.”
and animal guardians that these products are erinarian, relates a client’s experience: “We Acute symptoms of headache, nausea,
not absorbed into our dogs’ systems. The put Advantage on the backs of our dogs and and abdominal and lumbar pain are associ-
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5. ated with carbitol, one of the “inert” ingre- When Dr. Dobozy reviewed the reports to animals that are young, old, or suffering
dients in Frontline. According to the MSDS, from fipronil product studies, she found that from chronic disease. Animals with a height-
carbitol induced these symptoms in labora- Frontline “does not adequately describe the ened sensitivity to chemicals or with expo-
tory settings. severe reactions” reported by veterinarians sures from multiple sources such as a flea
Curiously, these potential side effects are – sloughing, “chemical burn” conditions, collar; other dips, sprays, dust, or flea
not published in the literature accompany- and extensively affected areas bombs; yard pesticides; and
ing the products, nor do many veterinarians well beyond the application site. house termite extermination,
know the dangers. But there are numerous When these incidents were re- are most likely to react. The
anecdotal reports from veterinarians in the ported, Merial recommended cumulative and synergistic
U.S. and the U.K. of dogs who were treated bathing the dogs. That’s strange, impacts of pesticides can
with spot-on products who have displayed because their literature indicates take a heavy toll on animals.
signs of neurological damage, such as de- the product remains effective after bathing. Dr. Jerry Blondell, of the US EPA Of-
pression, lethargy, convulsions, underactiv- The MSDS for Bayer’s Advantage tell fice of Pesticides, has indicated clearly “not
ity, tremors, overactivity, stiffened limbs, us that “prolonged contact with the skin can to use pesticides on the old, the sick, or the
and lameness. cause defatting of the skin due to solvent young.” While some of the literature for the
component in the products,” to “avoid skin spot-on products does discourage this us-
Adverse skin effects contact,” “to wear appropriate gloves when age, many dog guardians and veterinarians
Topical skin irritation is listed on all the handling the product,” and to “wash off any overlook or disregard these written precau-
MSDSs of the products reviewed in this ar- contamination.” tions.
ticle; however, product literature inserts fail Although the number of dogs reported
to emphasize the extreme nature of the prob- Chronic disease to react to these products may seem small,
lems. They all instruct the users that their Based upon toxicological studies, a dog suf- this does not suggest the overall impact is
products are for “external use only,” and to fering from liver, kidney, thyroid, adrenal, small. First, spot-on products are relatively
“avoid contact with the skin,” but only spleen, lung, brain or gonadal conditions new, and many problems are cumulative.
Merial’s product insert appears to suggest could experience heightened states of Second, reactivity to chemicals in a
there is some possibil- chronic diseases, with the potential for de- population is similar to other population sta-
ity of adverse skin con- velopment of cancer, when spot-on flea tistics and is represented by a bell-shaped
tact reactions. preparations are used. Permethrin is linked curve. In other words, at one end of the spec-
Dr. Dee Blanco, a to malignant liver and lung tumors and au- trum are sensitive individuals, and at the
holistic veterinarian toimmune system disease, and at very low opposite end are resistant individuals; these
practicing in New levels suppresses the immune system. Thy- groups are relatively small compared to the
Mexico, treated 20 roid lesions have developed in laboratory vast middle group, who show varying de-
dogs for adverse reac- studies in dogs during imidacloprid tests. grees of susceptibility – but who are all sus-
tions to Farnam’s flea product. In a letter to Further studies are necessary to understand ceptible. Thus the sensitive group – dogs
the Farnam regarding a client who had used the possibilities of malignancy. Thyroid can- who have displayed signs of toxicity – hap-
one of Farnam’s permethrin-based insecti- cer has been linked to fipronil, according to pen to be the sentinels for the younger,
cides, Dr. Blanco stated, “All the dogs (20 the EPA. The data from the metabolism and healthier ones who will eventually be af-
out of her 24 dogs treated with BioSpot ) chronic toxicity studies for fipronil indicate fected; it’s just a matter of time.
had pruritus (severe itching of the skin) with that “ . . . this is a persistent chemical and
bleeding and cracking of the skin, various has the potential for nervous system and thy- Safe alternatives
degrees of erythema (intense redness of the roid toxicity after long-term exposure at low Integrated pest management (IPM) is a non-
skin), many fluid vesicles (blisters), severe levels,” according to Dr. Dobozy. toxic approach used to eradicate any insect
hair loss, and elephantiasis (thickening of In the Journal of Pesticide Reform, au- infestation. Simply, it is a way of thinking
the skin) with chronic itching. Many also thor Caroline Cox cites studies that show about how to preserve the quality of life on
showed severe mental depression, lethargy, thyroid sensitivity to imidacloprid can re- this planet and within the earth’s stratosphere
and symptoms concomitant with aggravated sult in thyroid lesions, as well as increased – of understanding not only the damages of
liver toxicity. All symptoms appeared within incidences of miscarriages, mutagenic the pesticide to all species and the environ-
two weeks after applications of your (DNA damage) abnormalities, and abnor- ment, but also understanding the conse-
(BioSpot) product, also a consistent time- mal skeletons in animal studies. In addition, quences of insect resistance to the constant
frame for liver toxicity after absorption one metabolite (breakdown of the chemical parade of new, more sophisticated, and per-
through the skin. . . To date, most of the dogs into new chemical compounds during the haps more toxic pesticide formulas. The
have dramatically improved but a few still metabolism process in the body) of IPM process was initially designed to safe-
remain symptomatic.” imidacloprid appears to be far more toxic guard all species, including the environment,
Dr. Blanco also stated that one dog died to mammals than the imidacloprid itself. from the ravages of pesticides.
of liver cancer within three months of this In the next issue, we will present a
BioSpot application, which she says “could General risk factors complete indoor and outdoor IPM treatment
have been exacerbated by the application Of course, not all dogs exhibit immediately program for effective, non-poisonous flea
of BioSpot.” Permethrin is indicated as a noticeable symptoms when dosed with a control.
possible carcinogen by the EPA, causing commercial spot-on flea product. Adult ani-
liver enlargement and cancers in laboratory mals and those in the peak of health are less Kathleen Dudley is a writer and
mammals. likely to show immediate signs compared photgrapher, and lives in New Mexico.
22 | FEBRUARY 2002 Copyright© 2002, Belvoir Publications, Inc. TO SUBSCRIBE, CALL (800) 829-9165