Parasites in Dogs and Cats
Contents:
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Ancylostomiasis (hookworm) 
Ascariasis (roundworm) 
Coccidiosis 
Demodectic Mange 
Fleas 
Giardiasis
Lice 
Sarcoptic Mange in Dogs (scabies) 
Tapeworms 
Ticks 
Trichriasis (whipworm)
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Ancyclostomiasis (hookworm infection)
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General Information:
Hookworms are relatively common intestinal parasites of dogs, cats, and other animals.  Adult worms live in the small intestine, and their eggs pass out with the stool.  Diagnosis is by identifying the eggs during microscopic examination of the stool.
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Animals become infected with hookworms by eating infective eggs or larvae, penetration of the skin or footpads by larvae, or transmission of larvae from the mother while the fetus is still in the uterus.  The time from consumption of infective larvae to the appearance of eggs in the stool is 15-26 days.
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Hookworms are one of the most serious intestinal parasites, as they feed on the blood of their host animal and can cause severe anemia.  In young, weak, or malnourished animals, hookworms can cause sudden collapse and death.  Older, more resistant animals may suffer a slow, progressive, wasting disease.  Weight loss, diarrhea, and tarry or bloody stools frequently occur in animals with hookworms.
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Public Health Significance
Hookworm larvae can penetrate human skin and cause a skin disorder known as cutaneous larval migrans or creeping eruption.  This infection is not common, but anyone who develops a skin rash after being in contact with a pet with hookworms should consult a physician.
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Control Measures
1.  Stool samples should be examined microscopically at regular intervals.
2.  Good sanitation is essential.  Remove stools properly from the area where your pet is confined.
3.  Products are available for treating contaminated dog pens, runs, and tie-out areas.
4.  Heartworm preventative medications that also prevent hookworms and roundworms offer the surest method of hookworm control.
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Notify your veterinarian if any of the following occur:


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Ascariasis (roundworm infection)
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General Information:
Roundworms (ascarids) are the most common intestinal parasite of dogs and cats.  Pets become infected by swallowing roundworm eggs or larvae (immature worms) found in contaminated soil or feces or by eating infected rodents, birds, and certain insects.  Puppies and kittens are commonly infected by the mother while still in the uterus.  Swallowed larvae travel through the body to the intestine where they develop into mature worms.  There, adult females deposit eggs, which pass with the stool and develop into infective larvae.
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Diagnosis is by identifying the eggs during microscopic examination of a stool sample.
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Public Health Significance
Human infection with roundworm larvae (not adults) is possible but does not occur frequently if good hygiene is practiced, since eating contaminated stool or soil is necessary for infection.  Children should be taught the importance of cleanliness when playing with animals, especially litters of puppies and kittens.  The best insurance against human infection is keeping your pet free from roundworms by regular stool examination and treatment if necessary.
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Control Measures
1.  Stool samples should be examined microscopically at regular intervals.
2.  The stool should be checked for worms before females are bred.  Stool samples from puppies and kittens should be tested at or before weaning.
3.  Good sanitation is essential.  Remove stools properly from the area where your pet is confined.
4.  Eggs can remain infective in soil for years, so contaminated ground becomes a source of reinfection.
This is especially true of dog pens, runs, or areas where your pet may be tied.  Control measures for these areas include: 5.  Heartworm preventative medications that also prevent hookworms and roundworms offer the surest method of hookworm control.
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Coccidiosis
General Information:
Coccidiosis is a parasitic disease of the intestinal tract caused by a microscopic organisms called coccidia.  The disease spreads from one animal to another by contact with infected feces.  It is most severe in young or weak animals and often causes bloody diarrhea.
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Notify your veterinarian if any of the following occur:


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Demodectic Mange (demodicosis)
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General Information:
Demodicosis is a skin disease caused by a microscopic parasitic mite.  Demodectic mites are found in small numbers in the hair follicles of normal dogs.  In dogs with demodicosis, however, these mites proliferate, and large numbers inhabit the skin and hair follicles.  Dogs may acquire mites from their mother 2-3 days after birth.
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Demodicosis may involve only 1 or 2 small areas of the skin (localized mange) or large areas of the body (generalized mange).  Juvenile onset demodicosis occurs in dogs 3-12 months old, and the short haired breeds are most commonly affected.  Adult onset demodicosis generally occurs in dogs more than 5 years old and is often associated with internal disease or cancer.
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Localized demodicosis is the mildest form.  Usually only a few areas of hair loss on the head or front legs occur.  Most dogs with the localized form recover completely.  Generalized demodicosis is serious and often difficult to treat.  Large areas of the body may be affected, and often the affected areas are also infected by bacteria.  In these cases, the skin is red, crusty and warm, and has many pustules.  It may bleed easily and has a strong, rancid odor.  While most of these cases are curable, some can only be controlled and periodic re-treatment is necessary.
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Demodicosis also occurs as a chronic foot infection in mature dogs.
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Periodic rechecks and skin scrapings to test for active mites are necessary.  With the generalized form, bacterial cultures from the skin may be needed to determine the most effective antibiotic.
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Notify your veterinarian if any of the following occur:


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Fleas
General Information:
Fleas are small, brown or black, wingless insects with flattened bodies.  Several types of fleas infest the haircoats of animals, and some may occasionally feed on people.  These blood-sucking insects cause considerable irritation and distress to infested pets.  Severe infestations may lead to anemia from blood loss.  Fleas spread the common dog and cat tapeworm and carry several viral and bacterial diseases.
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Flea bites also cause skin allergies, rashes, and sores on both pets and their owners.
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The best places to look for fleas on your pet are the hindquarters, base of tail, stomach, and groin regions.  Sometimes no fleas are found but only tiny, black granules that resemble black pepper.  This material is flea feces and consists of digested blood ("blood crumbs").  To distinguish this material from dirt, smudge it on white paper or add a drop of water to it.  If you see a reddish brown color, your pet has fleas, even if you can find none.
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After taking a blood meal, fleas drop off the animal and deposit their eggs in cracks, crevices, and carpeting.  A single breeding pair of fleas may produce 20,000 fleas in 3 months. In 2-12 days, eggs hatch into larvae that feed in the environment.  Larvae molt 2 times within 2-200 days and the older larvae spin a cocoon in which they remain for 1 week to 1 year.  The long period during which the larvae remain in the cocoon explains why fleas are difficult to eradicate from the environment.  A hungry adult flea emerges from the cocoon.
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Many different products are available for flea control.  Many flea products are not compatible with each other and cannot be safely be used in combination.  Also some insecticides for dogs should not be used on cats.  To eradicate fleas, you must clean and vacuum living quarters well, especially where your pet sleeps.  Dispose of vacuum cleaner bag.  Apply the insecticide correctly and at proper intervals until the end of flea season.  All pets and the environment itself must be treated to eradicate fleas.  In severe infestations, it is advisable to employ a professional exterminator for house and yard treatment.
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Giardiasis
General Information:
Giardiasis is an intestinal disease of people, dogs, cats, and other animals.  It is caused by a microorganism called Giardia, which is swallowed when the animal eats contaminated stool, food, or water.  Giardia principally infects the upper small intestine.  Infected individuals pass the infective cysts in their stool, and the cycle begins again.
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Diagnosis may be difficult; therefore, repeated microscopic examinations of multiple stool samples are often needed to find the cysts.
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The most common sign of infection is persistent diarrhea, with pale, greasy, and occasionally blood tinged stool.  Giardia prevents proper absorption of nutrients, damages the delicate intestinal lining, and interferes with digestion.
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Laboratory tests are often required to evaluate the patientís response during and after treatment.  Sun exposure and drying help eliminate Giardia from your yard.
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Notify your veterinarian if any of the following occur:

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Lice
General Information:
Lice are small wingless insects that occasionally infest domestic pets.  The two main types of lice are the biting louse and the sucking louse.  Biting lice are very irritating to dogs and cats.  They do not penetrate the skin but feed on dead skin, body secretions, and hair.  Sucking lice penetrate the skin and feed continually on the animalís blood causing great discomfort.  If the infestation is heavy, the considerable blood loss may produce anemia.  Cats are not affected by sucking lice.
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Lice are very host-specific; dog and cat lice do not infest people.
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The female louse lays eggs and attaches them to your petís hair with a sticky substance.  These attached eggs, called nits, can be seen without magnification.  In 7-10 days the eggs hatch, and a miniature louse (nymph) emerges.  In about 3 weeks, the nymph matures and begins to lay eggs.  The entire cycle occurs on the infested animal.
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Treatment will be tailored to your individual petís needs.  Clipping the coat often facilitates removal of the nits and makes treatment with insecticides easier.  Combs and brushes should be kept clean, and other household pets should be checked for lice.
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Notify your veterinarian if any of the following occur:


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Sarcoptic Mange in Dogs (scabies)
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General Information:
Sarcoptic mange is a skin disease caused by a parasitic mite.  It is highly contagious and produces intense itching, reddening of the skin, thinning of the hair, and development of crusts and scabs.
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Bacterial skin infections commonly occur in the inflamed, irritated skin.
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Sarcoptic mites burrow directly into the skin, where they deposit eggs that hatch in 3-10 days.  The larvae burrow up to the skin surface to feed.  They molt into adults, which then mate and deposit more eggs in the skin.  The entire life cycle is complete within 3 weeks.  Sarcoptic mites prefer skin with little hair, so they are most numerous on the ears, elbows, abdomen, and hocks.  As the disease spreads, hair is lost and eventually the mites occupy large areas of the skin.
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Sarcoptic mites may also infest people in close contact with infested dogs.  Any people in contact with your dog who develop skin problems should consult a physician.  The mites can also infest cats and other dogs.
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Though the mites do not survive off the host animal for more than a few days, you should thoroughly clean the environment and use insecticidal sprays on kennels, shipping crates, harnesses, collars, and grooming tools.
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Notify your veterinarian if any of the following occur:


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Tapeworms
General Information:
The tapeworm is a parasite found in the intestines of dogs and cats.  It consists of a head and a long flat body made up of segments.  Segments are passed in the animalís feces, leaving the head still attached to the animalís intestinal lining, where it produces new segments.
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Tapeworm infestation may not cause noticeable illness in your pet, or it may produce digestive upsets, poor appetite, poor haircoat and skin, weight loss, and vague signs of abdominal discomfort.
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Tapeworm infection is diagnosed by finding the segments in your petís feces, in its bed, or clinging to the hair around the anus.  The eggs may not be found on microscopic examination of the feces.  When first passed, the segments are yellowish to white, about ¼ inch long, and may expand and contract.  When dry the segments resemble grains of rice.
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Tapeworms are not passed directly from pet to pet, but require an intermediate host in which to develop.  Common intermediate hosts are fleas and small animals such as mice, rats, squirrels, and rabbits.  Fish are the intermediate host for one type of tapeworm.
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Treatment will destroy the tapeworm already infecting your pet.  Reinfection is controlled by eliminating or reducing contact with intermediate hosts.  Do not allow your pet to eat small rodents or raw fish.
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Notify your veterinarian if any of the following occur:


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Ticks
General Information:
Ticks are blood-sucking parasites that infest most animals and sometimes people.  Their life cycle is complex and involves one or more species of animals as hosts.  Female ticks deposit their eggs in the environment, rather than on the animal.
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Ticks attach to the skin and feed on the animalís blood.  Tick bites may become infected, and some ticks produce a toxin that can cause paralysis and even death.  Ticks also spread several serious diseases of animals and people, such as Rocky Mountain spotted fever and Lyme disease.
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If only a few ticks are present on an animal, they may be plucked off.  Tweezers should be used to remove the ticks to prevent direct contact with your fingers, as ticks may carry organisms infectious to people.
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Notify your veterinarian if any of the following occur:


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Trichuriasis (whipworm infection)
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General Information:
The whipworm is a small thin worm that lives in the large intestine and cecum.  The cecum is a blind pouch located between the small and large intestine; it resembles the human appendix.  The whipworm gets its name from its body shape.  Its body is very delicate, and its tail tapers into a narrow "whip-like" structure.  It is difficult to see in the stool because of its size.
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Whipworms can cause diarrhea, bloody feces and poor general health.  Massive rectal bleeding occasionally occurs.  Diagnosis is by microscopic examination of the feces.  Sometimes several samples must be examined before the worm eggs are found.  It takes about 3-4 months after infection until the eggs are passed in an infected petís stool.
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Effective medication can cure your pet of whipworms.  However, good hygiene is required to prevent reinfection.  Stools should be properly disposed of daily.
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Notify your veterinarian if any of the following occur: