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Internal Parasites

Terms in this set (41)

Internal Parasites
Intestinal worms
Coccidia
Heartworms
Intestinal Parasites
Many cause significant damage to the host
Potential damage is often a function of the number present and location within the host
Parasitism is typically most severe in animals less than 1 year of age, but may affect all ages
Intestinal Parasites Common Clinical Signs
Life threatening anemia, Hypoproteinemia, Diarrhea, Vomiting, Intestinal obstruction, Decreased weight gain, Decreased milk production
Common Intestinal Worms Of Dogs And Cats
Hookworms
Roundworms
Tapeworms
Whipworms
Generalized Nematode Life Cycle
Adult stage-Parasite lives in definitive host
Preinfective stage- Free living stages or stages in intermediate host
Infective stage-Infects host
Preadult stage-Matures in host
Prepatent Period
Time from entry into host or infection until eggs are shed in the feces
Important to understand for treatment and control
Arrested Development
Stage that "hides" in tissue for period of time without development
Usually not affected by dewormers
Makes eradication of parasites difficult
Hookworms
Ancylostoma caninum-dogs
Ancylostoma tubaeforme-cats
Ancylostoma braziliense-dogs, cats
Uncinaria stenocephala-dogs, cats
Ancylostoma Caninum-Hookworm
Common parasite of puppies and dogs
Lives in small intestine. Prepatent period-2-4 weeks. Larva can be ingested, but more commonly penetrate skin. Transplacental and Transmammary infection common

Voracious blood suckers. Cause severe anemia and death in young dogs. Zoonotic-cutaneous larval migrans. Infections seen in children practicing poor hygiene. Infections seen in adults at beach where moist sand and "bare feet" allow larvae to penetrate skin
Ancylostoma Caninum-Hookworm Treatment
Panacur X 3 days
Pups-2, 4, 6, 8 weeks Pyrantel Pamoate
Adults-Monthly heartworm prevention
Ancylostoma Caninum-Hookworm Control
Larvae develop in the soil in warm climates
Clean feces daily. Do not keep infected dogs in dirt pens. Treat adults regularly. Impossible to decontaminate grass and soil
Roundworms
Toxocara canis-dogs
Toxocara cati-cats
Toxocara Canis-Roundworm
Common parasite of puppies and dogs
Adult parasites are large, up to 15 cm
Eggs are highly resistant to damage in the environment. Infected larva ingested

Zoonotic. Visceral larval migrans. Ocular larval migrans. Humans infected by ingesting infective larva from environment. Children playing in dirt or sandbox
Toxocara Canis-Roundworm Clinical Signs
Large numbers spread transplacentally, transmammary. Lives in small intestine. Can cause severe abdominal discomfort in nursing pups. Large numbers of worms can appear in feces and vomitus. Obstructed intestine with rupture and death possible
Toxocara Canis-Roundworm Treatment
Treatment: Pyrantel, Panacur X 3 days
Pups-2, 4, 6, 8 weeks Pyrantel Pamoate
Adults-Monthly heartworm prevention
Trichuris Vulpis-Whipworm
Less common parasite
Eggs extremely resistant in environment
Live in large intestine. Cause diarrhea, weight loss
Can cause severe illness and death. Larvated eggs are ingested. Prepatant period- 3 months
Trichuris Vulpis-Whipworm Treatment
Panacur X 3 days, repeat in 3 weeks, repeat in 3 months. Milbemycin heartworm prevention
Tapeworms Taenia spp.
Mild disease as compared with other intestinal worms. All species have intermediate hosts in which the larval stage develops. Taenia's intermediate hosts are mice, rats, other small rodents
Taenia Management
Treatment: Panacur X 3 days, Praziquantel
Control: Eliminate ingestion of intermediate hosts
Reasons for treatment "failure"
Already to far infected
Dipylidium Caninum
Dipylidium's intermediate host is the flea
Fleas commonly ingested while grooming
Dipylidium is zoonotic if flea is ingested
Prepatant period 2-3 weeks
Dipylidium Caninum Treatment
Treatment: Praziquantel
Control:Flea control
Reasons for treatment "failure"
Tapeworms
Most easily diagnosed by seeing segments around rectum or in stool.
Eggs sometimes seen on fecal flotation.
Coccidia
Single-celled parasites
Infect intestines
Reproduction: Sexual and Asexual
Coccidia Clinical Signs
Cause mild diarrhea with occasional blood in healthy pups and kittens. Can be life threatening to stressed young. Clinical signs can be similar to parvo - bloody diarrhea

Common in areas with group housing such as breeding kennels and humane societies
Major problem for young puppies and kittens in breeding kennels and humane societies
Coccidia Treatment
Treatment: Albon for 10 days
Control:Hygiene
Intestinal Parasite Exam
Commonly called fecal exam
Test for parasites inside-endoparasites
Parasite eggs, oocysts, larvae, tapeworm proglottids and adult parasites can be seen
Fecal Flotation Test

A solution of zinc sulfate, sugar, or other solute which has higher specific gravity than water is mixed with feces and the eggs float to the top.
The eggs float to the coverslip which is then removed and examined under a microscope
Intestinal Parasite Exam Equipment Needed
Fecal Sample,Fecalyzer, Rubber Gloves, Microscope, Microscope Slide, Cover Slip.A sample of 1-2 grams is necessary. Often obtained with fecal loop.
Intestinal Parasite Exam Directions
1) Properly obtain fecal sample
2) Visually inspect sample for any worms or worm segments
3) Lift cap of Fecalyzer and remove green insert
4) Place sample into bottom part of green insert
5) Place insert back in Fecalyzer
6) Add Fecasol solution to the tip of the arrow on the side of the Fecalyzer
7) Rotate green insert
Intestinal Parasite Exam Directions pt. 2
8) Add more fecasol solution until the isert is full, forming a convex meniscus
9)Put coverslip on top of Fecalyzer
10)Label sample with patient identification.
11)Allow to sit for 10-15 minutes.
12)Put coverslip on microscope and place slide under the microscope.
13)Look for Parasite eggs starting under lowest magnification and work your way up to 40x.
14)Examine all areas of slide.
Parasite
Definition-an organism who lives upon or within another organism at whose expense it obtains some advantage. Symbiosis in which one population adversely affects another, but cannot live without it. Host's expenses can be trivial or cause death
Dirofilaria Immitis- Heart Worm
Parasitic disease affecting dogs, cats, foxes, coyotes, and rarely man. Dogs are natural host
Mosquito is vector and intermediate host
Worldwide range wherever dogs and mosquitoes are prevalent and temperatures are warm enough to support growth within the mosquito vector
Heartworm Disease Life Cycle
Transmitted by mosquitoes
Adult heartworms reside in the pulmonary arteries or right ventricle and produce microfilaria
Microfilaria circulate in the blood

The microfilaria are ingested by feeding mosquitoes in blood meal. Microfilaria molt in mosquito over 2 weeks. Microfilaria must undergo changes in mosquito to infect dog - L3 stage
6-9 months life cycle: Larvae stage change in mosquito depending on temperature and humidity
Heartworm Disease Life Cycle pt. 2
Average daily temperature must be around 65 degrees for microfilaria to mature in mosquito
Can heartworm disease be spread by blood transfusions? No
The infective larvae are transmitted back to the dog during feeding.

The larvae initially stay in the subcutaneous tissue mature and enter the vascular system and migrate to the heart and lungs where final maturation occurs. Completion of life cycle takes 6-9 months
Heartworm Disease - Dogs Pathology
Heartworms reside in the right ventricle, pulmonary arteries. Thickening, decreased diameter, inflammation of pulmonary artery
Secondary pulmonary hypertension.
Right side heart failure with ascites
Thromboembolism due to dead worms
HeartWorms on heart
Secondary pulmonary hypertension. Right side heart failure with ascites
Heartworm Disease-Clinical Signs in Dogs
Low worm burdens are asymptomatic
Anorexia, Weight loss, Chronic cough
Exercise intolerance, Ascites, Syncope
Heartworm Disease - Dogs Diagnosis
Microfilaria Detection
Direct Blood Smear - place whole blood on microscope slide
Heartworm Disease - Dogs Tests
Antigen Test - Gold Standard
Good Sensitivity and Specificity
Detect antigen from adult female heartworms.

Limitations:Negative for the first 5-8 months of infection until adult females are present
All male infections will be negative. Low worm burdens may test negative

Radiography-Most objective method of assessing the severity of heartworm cardiopulmonary disease. Right heart enlargement.Torturous pulmonary arteries
Heartworm Disease - Dogs Treatment
Melarsomine (Immiticide)- adulticide
Give 1 dose IM then follow 1 month later with 2 doses IM 24 hours apart
Only approved adulticide

Ivermectin-Weekly to biweekly doses can provide effective kill but not the best option in most cases
Different Dewormers
Pyrantel Pamoate-"Strongid". Yellow liquid
Hookworms & Roundworms

Fenbendazole-"Panacur" or "Safegard"
White liquid.Give for 3 consecutive days
Hookworms, Roundworms, Whipworms, Taenia

Praziquantel-"Droncit" or "Drontal"
Pill, liquid, injectable
Tapewoms, Taenia, and Dipylidium
Heartworm Prevention
Heartgard Plus-Ivermectin plus Pyrantel
Interceptor-Milbemycin
Advantage multi-Moxidectin
Revolution-Selamectin
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