Cedar Way Veterinary Clinic, Ltd.
PARASITES

Parasites come in many forms and affect various parts of the body.
Geographical location, lifestyle, housing conditions and species play a
role in which parasites are likely to be a problem for your pet. The
parasites discussed in on this page are those we need to be aware of in
our geographical area.
For more information about zoonosis, visit www.capcvet.org.
Some parasites can be avoided by diligent routine prevention programs.

I. EXTERNAL PARASITES:
Fleas are a major problem in  our area.
Ticks hikers and camping enthusiasts may find ticks on their pets as well as pets running
in the fields and forest preserves.
Mites... Ear mites (often seen in young cats) and Demodex mites (puppy mange) are quite
common;  Sarcoptes  (scabies – contagious to other pets as well as people) and
Cheyletiella mites are less of a problem.  These parasites tend to be medically managed if
they occur, rather than by routine prevention.

II. INTERNAL PARASITES:
Intestinal parasites include Roundworms, Hookworms, Whipworms and Tapeworms.
Giardia and Coccidia are common parasites that are often seen.

PARASITE PREVENTION
Through routine screening (at least annual fecal checks and blood tests for heartworm)
and the use of safe, effective preventive products such as Iverhart Plus and Frontline can
keep parasites at bay!  Parasites need their host animal in order to exist. It is not in a
parasites' best interest to kill its host (although this can, and does happen), however, they
often result in a less than optimal physical condition. Poor hair coat, inflamed itchy skin,
intermittent diarrhea and poor physique can be markers for parasitism. In many cases the
host can appear perfectly normal while harboring and spreading these organisms.
Fecal parasite examinations can detect if your pet currently harbors intestinal parasites. If
the actual worm or their eggs are detected upon this microscopic examination appropriate
medications can be dispensed to treat the infection. It is encouraged to have a stool
sample brought in with you.
Blood tests can detect the presence of heartworm. In addition to this routine test, our
Adult Awareness and Senior Wellness blood tests may uncover other hidden diseases in
your pet.
Flea combs can be used to detect superficial parasites.
Skin scraping is required to detect mites that dwell deep in hair follicles.

I. INTESTINAL PARASITES...

ASCARIDS: These worms, commonly referred to as roundworms, are among the largest and
most familiar of nematode parasites infecting domestic animals. Toxocara cati and
Toxascaris leonina infect cats and Toxocara canis infects dogs. These parasites are
contracted directly from an animal’s mother via placental migration or from the milk, or by
ingesting parasite eggs. The eggs of these worms are very hardy and can remain in the
environment for long periods of time up to many years. Once into the host animal these
parasites migrate through the body before finally coming to rest in the small intestine. This
migration takes from 1-2 months depending on the worm involved. If T. canis eggs are
eaten and hatch in the host stomach they then migrate through the gut wall, enter the
portal blood stream and wander about in the liver parenchyma for a while. They then enter
the caudal vena cava and are transported to the heart and lungs. When they reach the
lungs they break out of the capillaries and enter the alveoli. At this point they molt into a
third stage larva and ascend the bronchial tree and trachea to the pharynx. They are then
swallowed, go through two more molts and end up in the small intestine. This pattern of
migration is termed tracheal migration. However if the larvae fail to break into the lung
alveoli they return to the heart via the pulmonary veins and are scattered throughout the
body by the systemic circulation. This is called somatic migration. This differentiation of
route is very important. In young dogs most larvae will follow the tracheal route and end
up in the intestine. In adult dogs, most will end up in the tissues as arrested second stage
larvae. If the egg is ingested by an inappropriate host such as a human the larvae will also
end up in the host tissue. If a small animal such as a mouse eats the eggs it ends up as a
larval stage in the mouse tissue. Then if that mouse is eaten by a dog the encysted larval
forms develop in the dog’s intestine. This is referred to as mucosal migration. Migration
and encystment of second stage larvae in inappropriate hosts and transmission via
predation is also seen in T.cati and Toxascaris leonina. The encysted second stage larvae
in the host tissues are hormonally triggered in the third trimester of pregnancy to migrate
to the mammary tissue and uterus where they are passed to the unborn pups. These
parasites are mature by the time pups are three weeks of age. Nursing bitches can be
infected with immature forms shed in the feces of their pups. Thus it can be seen that
ascarids are very well developed parasites with several modes of transmission! Although
there are minor differences, T.cati and Toxascaris leonina behave in a similar fashion.

ASCARID LIFE CYCLE

CLINICAL SIGNS:
Parasites depend upon their host for survival. Thus it is in the parasites best interest not
to kill its host. However large infestations of ascarid worms can cause significant
problems. Large numbers can cause obstruction of the small intestine. They can migrate
into and obstruct the bile duct. The tracheal migration route can result in damage to the
liver and/or lungs. An owner may notice a general unthriftiness and poor quality hair coat.
With heavy infestations worms may be vomited or passed in the stool. In the majority of
pets with ascarid infections no outward signs are apparent. In these cases detection and
diagnosis requires a microscopic examination of the feces. Fecal material is mixed with a
concentrated salt solution. The worm eggs float to the surface of the solution and can be
collected for microscopic examination. The appearance of these eggs is specific to the
type of worm carried by the host. Once eggs are identified appropriate treatment can be
initiated.

VISCERAL LARVA MIGRANS:
Human Toxocarosis results from paratenic host second stage larvae somatic migration. In
man the migrating larvae develop nodules which occur primarily in the liver, kidneys, brain
and lungs. They can also occur in the eyes causing granulomatous retinitis. They are
associated with a sustained eosinophilia and clinical signs based on organ involvement.
Children are at the greatest risk of infection. The typical epidemiological situation involves
a toddler soil contaminated with ascarid eggs. As mentioned previously these eggs are
hardy and exist for a long time in soil. Soil in the vicinity of habitual canine defecation sites
and public parks visited by large numbers of dogs tend to be highly contaminated.  
Although T.cati is less of a risk than T.canis, it has also been associated with Visceral Larva
Migrans. Therefore it is advisable to keep toddlers from playing in areas where dogs and
cats habitually defecate. For this reason dog and cat feces should never be used to
fertilize vegetable gardens! The bagging and responsible disposal of dog and cat feces
helps to lessen environmental contamination with ascarid worm eggs.

TREATMENT:
Most dogs and cats will be infected with roundworms at some point in their lives. As pups
and kittens worms are passed from their mothers and as adults they are picked up from
eating feces, contaminated soil and via predation of infected small mammals. There are
many safe and effective anthelmintic products (deworming) available for treating
roundworms. Pups and kittens can carry egg producing adult worms as early as three
weeks of age. The mothers of nursing offspring are also likely to be shedding ascarid
eggs at this time. In order to minimize environmental contamination testing, and if
required, worming should begin at an early age and continue at regular intervals
throughout a pets' life.
We will deworm your pet with the best appropriate products available. These are safe,
easy and effective. Many are broad-spectrum addressing most of the intestinal worms
seen in our area. We prefer to run a fecal parasite examination before using any product.
Iverhart Plus is a heartworm prevention product that also eliminates nematodes. It is an
excellent means of routine ascarid control. Ask us for advise on the best way to control
these parasites in your pet..


CESTODES: These worms are commonly referred to as tapeworms. They are long,
segmented worms that anchor themselves to the wall of the small intestine. They form
segments (egg cases) that move down the bowel with feces. These segments,
approximately 1/8 inch long and flat, come out with the feces and crawl about on the pet’s
hair around the anus. They dry out and end up looking like a grain of brown rice. Once in
the environment these desiccated egg cases crack open dispersing minute tapeworm
eggs. The eggs are ingested by intermediate hosts (fleas and small mammals) and the
lifecycle repeats itself. Some tapeworms can complete their lifecycle in less than two
weeks! Control requires treatment of the pet, elimination of infected fleas.


HOOKWORMS: Ancyclostoma caninum is commonly referred to as the hookworm. Adult
worms occupy the small intestine and eggs are passed in the feces. Environmental
contamination plays a major role in the transmission of hookworm. The eggs hatch outside
the host and infective can enter the host via ingestion, direct penetration of the skin or,
as with ascarids immature stages can be passed directly to pups. Clinical signs vary from
subclinical to per acute depending on the number of parasites and the health of the host.
Any dog showing signs of anemia and contact pattern skin irritation should be checked foe
hookworm infestation. Diagnosis is made by via fecal floatation and egg recognition. The
environment can be treated using sodium borate or sodium hypochlorite. Animals infected
with hookworm can be safely and effectively treated. Prevention of this parasite is done
with the Heratworm preventive medication – Iverhart Plus given year ‘round. Severely
debilitated dogs will need to additional supportive care as required.


WHIPWORMS: Tricuris vulpis is a nematode commonly called whipworm or threadworm.
The adults, fine curved worms, are found in the large intestine. The lifecycle is simple and
direct. Eggs are passed in the stools and an infective first stage larva develops in about a
month. This larval form does not hatch from the egg unless it is ingested by a dog. Egg
laying adults can be found in the large intestine 10-12 weeeks after ingestion. As with
ascarids, the eggs are quite resistant so that dogs living in infested environments tend to
become reinfected. Whipworm infections are usually asymptomatic but heavy infections
can cause recurrent diarrhea, often with mucus and flecks of blood.  As with other
intestinal parasites diagnosis depends on identification of eggs passed in the feces. Due
to the hardiness of the eggs and the long prepatent period,additional precautions and
controls are done.


PROTOZOANS:

GIARDIA... As with other protozoans Giardia is a single celled organism. It is a tear drop
shaped cell that is adapted for attachment to the mucous epithelial cells of the small
intestine. This trophozoite phase is occasionally found in the feces of infected animals,
but mature Giardia cysts are more commonly seen. Contaminated water is the most
common source of infection. Clinically animals with Giardia vary in symptomology from
aclinical to severe enteritis and weight loss. Giardia can also cause enteritis in man. This
protozoan is rarely found with simple fecal floatation techniques. Direct wet smear
examination of fresh feces or a fecal concentration technique yield the best results.
Effective treatment can be accomplished.
COCCIDIA... There are many species of coccidia all of which are quite host specific.
Isosporan coccidia such as I.felis have a relatively simple life cycle. Infective oocyts are
shed in the feces. These can be ingested by the cat or a paratenic host such as a mouse.
When the cat eats the mouse it becomes infected with infected cysts from the mouse
tissue. The immature forms invade the host gut cells where the asexual phase of the life
cycle takes place. It is followed by the sexual phase resulting in oocyte formation and the
destruction of host cells. Toxoplasma gondii has a more complex life cycle. Various stages
of this parasite are capable of infecting both the definitive and intermediate hosts. They
can cause extra-intestinal as well as intestinal infection in the definitive host. In addition it
can pass transplacentally to the unborn. Diagnosis is via fecal floatation and oocyst
identification. These organisms can be carried asymptomatically but they can also be
associated with diarrhea. On rare occasions rapidly acquired, heavy infestations can be
fatal before any oocyts have been shed in the feces. Coccidial infections respond well to
treatment with sulpha based antibiotics.
Human Toxoplasmosis: T.gondii is capable of extensive parasitism of tissues outside the
gut. Following acute infection, cysts persist for long periods of time in many body tissues.
Humans can contract T.gondii from infected cat feces or from ingesting uncooked meat
containing toxoplama cysts. If pregnant women become infected it is possible for the fetus
to be infected transplacentally.

II. HEARTWORM...
DIROFILARIA IMMITIS... Commonly termed heartworm, is a major concern in many areas of
the world including our area. Canines are the species most at risk however heartworm
incidence in cats is increasing and it has been found in man. Mosquitoes are the
intermediate host (vector) in the transmission of this disease. Thus climate and
environmental factors must be favorable to mosquitoes for heartworm to be endemic.
Large adult worms reside in the right heart, pulmonary arteries and caval veins. They
release microscopic microfilaria into the circulating blood. When the animal is bitten by a
mosquito microfilaria are ingested along with the blood mea. In 10-30 days infective third
stage larvae enter the mosquito's salivary glands. When it takes its next meal these
HEARTWORM LIFE CYCLE

The presence of  large adult worms cause physical obstruction plus pathological changes
in the pulmonary arterial tree. Infected animals fatigue easily, cough and appear unthrifty.
Diagnosis is done by testing a small blood sample for antigen detection. At WBVC we use
the SNAP test for detecting adult infection. This is more accurate than testing for
microfilaria as some animals can have adults without circulating microfilaria; occult
heartworm infection. Even with the most up to date testing methods an animal can be
carrying early stages of the disease for six months before detection is possible!  Infected
animals can be treated, in hospital, with injections of Immiticide. This procedure is not
without risk, time consuming and costly. Prevention is the preferred route of action. At
Cedar Way Veterinary Clinic we advise routine testing and the use of heartworm
prevention products such as Iverhart Plus YEAR ‘ROUND. As these products also help
control roundworms and hookworms use this once a month prevention throughout the
year.

I. FLEAS....
Fleas are very common parasites in the New Lenox area. Most pet owners are only too
aware of their presence! The adult flea spends most of its life off the animal... feeding on
the animal’s blood and reproducing. Female fleas can lay up to 40 eggs per day. These
eggs fall off the pet into carpets, cracks and furniture (or if outdoors onto the ground).
Within 1 to 10 days the eggs hatch into larvae. These look like fine, dark, wiggly threads
about 1/2cm long. The larvae feed on organic debris for 5-11 days before forming a
cocoon. It is during the larval stage that they can consume tapeworm eggs and become
the intermediate host for the development of tapeworms... more on that later. The cocoon
stage protects the flea as it transforms into an adult. This stage (pupae) is very resistant to
insecticides. Fleas can emerge as quickly as 12 days or, if conditions are less than optimal
pupae can remain dormant in excess of 18 months! It is the insecticide resistance of the
pupal stage that has made flea control so difficult in the past. Products such as Frontline
Plus will help control this. Once hatched the baby fleas quickly seek a blood meal and the
cycle starts anew!
It is recorded that 10 adult fleas can multiply to more than 250,000 fleas in only 30 days!
Given these figures it becomes easy to appreciate the need for prevention. As with many
things... "An ounce of prevention is worth a pound of cure".

DOES MY PET HAVE FLEAS?
If your pet is scratching or has irritated skin it may have fleas. If you have red bites on your
feet and ankles... your pet may have brought fleas into your home. Dog and Cat Fleas do
not live permanently on humans, however, if a human is handy and a flea is hungry it will
not hesitate to take a meal where it can find it.
It is fairly simple to check for fleas. You can run a flea comb down your pets back to the
base of tail... take care to get right through to the skin. You may see live fleas or perhaps
just the excrement left behind where it took its meal. Flea excrement looks much like
finely ground pepper. As it is a digested blood meal, if you put some on a damp white
tissue you can see that as it dissolves it leaves a rust colored stain on the tissue. Another
method is to put your pet on a clean light colored surface and give it a good rub in all
directions... really stirring up the hair coat. If you then see black specks on the light
colored surface and these are positive for the tissue test... then your pet has fleas. In
some cases the flea infestation will be great enough that you can see the little devils
scurrying about on your pet. They are usually most visible in the groin area.
Fleas are blood sucking wingless insects. They are somewhat smaller than a sesame seed
and are flattened side to side. They have powerful hind legs enabling them to jump long
distances. They can jump onto their host from infested indoor and outdoor areas and from
other animals, both domestic and wild.

THE FLEA LIFE CYCLE:
Effective Flea Control is based on the life cycle of the flea.         
STAGE        % of TOTAL POPULATION
ADULT        5
PUPAE        10
LARVAE        35
EGGS        50
Eggs are what make up the largest portion of the population. If they are not laid in the first
place, or if they are prevented from hatching, flea control can be accomplished.

FLEAS and DISEASE:
Fleas are the number one cause of skin disease in pets. These blood sucking parasites
inject minute amounts of saliva when they take a blood meal. This results in an irritation
and causes your pet to chew and scratch. This damages the skin and allows for secondary
bacterial infections to occur. If your pet is scratching be sure to check for fleas! Fleas will
also take a meal from humans, resulting in an itchy swelling where the bite was inflicted.
Fleas are the intermediate host for tapeworms. Tapeworm egg cases are passed with
animal’s feces or directly from the anus. They dry out and release tapeworm eggs into the
environment. The larval stage of the flea ingests the eggs and an intermediate stage of
the tapeworm develops in the growing flea. When your pet is itchy it chews at itself and
ingests the flea, along with its baby tapeworm. The tapeworm then completes its lifecycle
in your pet's intestine.
Fleas live on blood and in severe infestations can consume enough blood to cause
anemia. Animals that are very young, old or debilitated are at greater risk for debilitating
blood loss.

FLEA CONTROL:
Fleas can be found on the pet and in its environment. As a result an effective flea control
program must address both the pet and its premise. The key to understanding effective
control, or treatment, is knowledge of the flea lifecycle. Vist www.frontline.com for more
information.
It became apparent that failure to control fleas would result unless the pet and the
environment were treated simultaneously, with products that were safe, effective and
user friendly. These products are now available and flea control is no longer a mammoth
and hazardous task. Frontline (fipronil) is making history of flea infestations!
Shampoos, adulticide collars, sprays, mousses and powders are still available and can be
useful under certain circumstances. They contain such ingredients as pyrethrins,
pyrethroids, carbamates and organophosphates.
Natural insecticides are available, however most claims of effectiveness are purely
anecdotal. The include ingredients such as rosemary, wormwood, pennyroyal, eucalyptus,
citronella and diatomaceous earth. Products derived from citrus pulp such as d-limonene
and linalool have been marketed but have also been implicated in some cat deaths!
Although safe Brewer"s yeast, thiamine and garlic have not proven effective in clinical
trials. Avon Skin So Soft, in diluted form (5%), has proven to act as an insect repellent but
does not kill fleas.
Premise and environmental control products are useful in affecting a rapid start when
combating an existing flea infestation.
We recommend you contact us prior to purchasing any flea control products. The
appropriate product(s) will depend on the species, age and health of your pet combined
with the severity of the flea situation and your pet’s lifestyle. This information is available
from the staff of Cedar Way Veterinary Clinic. Salespersons in pet store outlets do not
have the knowledge of a trained veterinarian. Seek the products that are best suited to
your pet, safe and appropriate for your situation.


II. TICKS....
All ticks are bloodsucking parasites. Although there are several different types of ticks,
each has four stages of development in its lifecycle. These four stages are: the egg, the
six-legged larva, the eight legged but sexually immature nymph, and the eight legged
sexually mature adult. The types of ticks vary in how many different host animals they visit
during this lifecycle. Some one host ticks go from larva to adult on one host animal, others
drop off their host after the nymph has fed to seek another host for the remainder of the
lifecycle... these are termed two host ticks. There are also three host ticks whose larvae
and nymphs drop off after feeding. This cycle can span several weeks to two years.
Two and three host ticks can spread disease interstadially ; that is the disease organism is
carried by the tick as it transforms from one developmental stage to the next. One host
ticks transmit disease by passing organisms from an infected adult female tick to her
progeny transovarially.
Tick populations and the diseases associated with them vary demographically. Lyme
disease is a concern is many areas of the country. This can be treated with antibiotics if
caught early. There is also a vaccination available for prophylactic control. Elsewhere ticks
are associated with tick paralysis, Babesiosis, rickettsial diseases, viral diseases and
bacterial diseases.
Pets most at risk are those exposed to grassy and woody areas populated by wild animals.
You may see nymphs or adult ticks on your pet as both phases feed on animals. The unfed
ticks come onto your pet looking like a small crawling bug... the immature stages being
smaller than the adults. Once attacked to your pet and feeding they swell up until they look
first like a dried raisin and then like a well plumped one. When they finish feeding they
leave and inflamed area where they penetrated the skin.


TICK CONTROL:
Frontline are formulated to kill ticks before they become firmly attached. Your pet’s age,
health and lifestyle should be considered in order to determine if these products are
required, and safe, for your pet. Ask us for details.


III. MITES....
Mites are minute arachnids requiring magnification for identification. They can affect most
species, causing inflammation and irritation of the integument. Some mites spend their
entire lifecycle on the host while others can live for several days off the host. At this time
mites are dealt with reactively rather than proactively. It is the pet owners responsibility to
detect a possible problem, however effective treatment requires an accurate diagnosis.

OTODECTES... These ear mites are seen primarily in cats. They are spread from cat to cat.
These mites cause severe inflammation of the ear canal. The ears are itchy and the cat will
scratch the ear, sometimes to the extent of causing open sores in the skin behind the ear
pinna. The canal itself becomes filled with dark gritty debris. Treatment involves
irradicating the mites plus cleaning and medicating the ear canal. Medications can be
used to kill ear mites. These mites can live for a short period of time outside of the ear
canal on the cat and in the environment. In cases of persistent reinfection it may be
necessary to treat the premise but with newer products this is generally not required.


DEMODEX... These mites affect dogs and on occasion cats. These host specific parasites
live deep within the hair follicles and glandular ducts. They are transmitted to nursing
pups via direct contact with the dam soon after birth. Most healthy animals harbor small
numbers of these mites. In some dogs the immune system does not keep their numbers in
check and the mites multiply to numbers that cause clinical disease; Demodectic mange.
This is evidenced by patchy areas of hair loss often on the face and forelimbs. The
localized form can become secondarily infected with Staphylococcal bacteria. This
generalized form can cause severe illness. In some cases of localized demodex the body
will eventually develop an adequate immune response and spontaneous remission will
occur. In the past treatment has been difficult, hazardous and not terribly effective.
Although an "off label" use, oral Ivermectin administered for 60-90 days appears to be a
relatively safe, effective and easy way to treat demodex infections. Because it is thought
that animals suffering from Demodectic Mange are immuno-compromised, it is advisable to
spay/neuter them in case there is an inherited trait.

CHEYLETIELLA... Often called "walking dandruff" these mites cause inflammation, itching
and a mealy dandruff especially along the back. It can occur in many species, but is seen
most often in rabbits and dogs. These mites can live for short periods of time off  the host.
Treatment involves the use of topical or injectable insecticides. On occasion premise
treatment is required.

SARCOPTES...   Sarcoptic mange is intensely itchy and can be passed between dogs and
humans. These mites often cause crusty lesions on the ear tips and red itchy spots on the
ventral abdomen. Although they can be treated with topical products, injectable
insecticides are very effective. This form of mange is rarely seen in our practice.