pfizer atlas of veterinary clinical parasitology...veterinary clinical parasitology isbn...

PFIZER ATLAS OFVETERINARY CLINICAL

PARASITOLOGY

Pfz Parasite Atlas FNL.qxd 5/28/04 11:34 AM

Byron L. Blagburn, MS, PhDCollege of Veterinary Medicine

Auburn University

Michael W. Dryden, DVM, PhDCollege of Veterinary Medicine

Kansas State University

Editors

Animal Health

PFIZER ATLAS OFVETERINARY CLINICAL

PARASITOLOGY

ISBN 0-9678005-3-6


1

CONTENTS

Published by The Gloyd Group, Inc.Wilmington, Delaware

Medical illustrations created by Allison Lucas Wright, MS, CMI and Gene Nunnally Wright, MS, CMI, Athens, Georgia

All photographs courtesy of Byron L. Blagburn, MS, PhD

© 1999 by Pfizer Inc.All rights reserved. First printing, 2000

Printed in the United States of America.

INTERNAL PARASITES 34–5 ............Heartworms, Canine

6–7 ............Heartworms, Feline

8–9 ............Hookworms

10–11 ............Whipworms

12–13 ............Roundworms

14–15 ............Dipylidium Tapeworms

16–17 ............Taenia Tapeworms

18 ............Giardia

EXTERNAL PARASITES 1920–21 ............Fleas

22 ............American Dog Ticks

23 ............Brown Dog Ticks

24 ............Deer Ticks

25 ............Common Ticks Compared

26 ............Ear Mites

27 ............Demodex Mites

28 ............Cheyletiella Mites

29 ............Sarcoptes Mites

INTERNAL ORGANS (Canine & Feline) 30 -31

UNDER THE MICROSCOPE 3334–45 ............Photographic aids to identifying common parasites and

pseudoparasites as seen in blood, feces, and urine

The hosts for each parasite are identified at the top of each page by the following icons representing dog, cat, and/or human hosts.

Pfz Parasite Atlas FNL.qxd 5/28/04 11:34 AM Page 4

3

INTERNAL PARASITES4–5 Heartworms, Canine

6–7 Heartworms, Feline

8–9 Hookworms

10–11 Whipworms

12–13 Roundworms

14–15 Dipylidium Tapeworms

16–17 Taenia Tapeworms

18 Giardia


5

HEARTWORMS—CANINEDirofilaria immitis

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HEARTWORMS—CANINEDirofilaria immitis

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CANINE HEARTWORM INFECTION

Dog heart infected withadult heartworms

➤

Normal dog heart

➤

A mosquito depositsheartworm larvae via saliva puddle into bloodstream.

A mosquito becomes a heartwormintermediate host by ingesting microfilariaewhile biting an infected host.

➤

➤

Adult heartworms live inthe right ventricle andpulmonary artery.**

➤

CANINE HEARTWORM*

Larvae develop intissues and migrateto the heart wherethey mature to adult worms.

Length of Life Cycle = Approximately 6 Months

Fertilized adultfemale heartwormsrelease microfilariaeinto the blood.

* Although rare, humans may develop pulmonary lesions if infected with D. immitis.

** Adult worm is sometimes found at ectopic sites, eg, eye, skin, or body cavity.


6

HEARTWORMS—FELINEDirofilaria immitis

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7

HEARTWORMS—FELINEDirofilaria immitis

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Feline heart and lungs infectedwith adult heartworms.**

➤

FELINE HEARTWORM* FELINE HEARTWORM INFECTION

Cat heart and lungsinfected with adult

heartworms

➤

Normal cat heart and lungs

➤

Length of Life Cycle = Approximately 8 Months

A mosquito depositsheartworm larvae via saliva puddle into bloodstream.

A mosquito becomes a heartwormintermediate host by ingesting microfilariaewhile biting an infected host.

➤

➤

Larvae develop intissues and migrateto the heart wherethey mature to adult worms—however, many ofthe larvae do notreach maturity incats.

Fertilized adultfemale heartwormsrelease microfilariaeinto the blood.Microfilariae aredifficult to detectbecause they arefew in number andare present in bloodfor a short time.

* Although rare, humans may develop pulmonary lesions if infected with D. immitis.

** Adult worm is sometimes found at ectopic sites, eg, peripheral arteries, body cavity, or central nervous system.


8

HOOKWORMSAncylostoma caninum,* Ancylostoma braziliense,* and Ancylostoma tubaeforme*

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HOOKWORMS

Following ingestion of infectivelarvae in the mother’s milk,puppies begin passing eggs in thefeces in as little as 2 weeks.

Young animalsmay be infectedduring nursingvia milk, byingestion ofinfective larvaein the soil, or byskin penetration.

Eggs hatch and larvaedevelop to infective stage.

➤

Infective larvae are ingested or penetrate the skinand may migrate extensively.

➤ ➤

9

HOOKWORMSAncylostoma caninum, Ancylostoma braziliense, and Ancylostoma tubaeforme

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HOOKWORM INFECTION

➤

Small intestineinfected with

hookworms

* The life cycles for A. tubaeforme and A. braziliense aresimilar to that shown for A. caninum; A. tubaeforme isgenerally found only in cats; A. caninum and A. brazilienseare found in both dogs and cats; larvae of A. braziliense andA. caninum may cause human cutaneous larva migrans andrarely, eosinophilic enteritis.

Length of Life Cycle = 3 to 4 Weeks

➤

Larvae mature to adult hookworms thatreside in the small intestine, where they

can cause significant blood loss.

➤

Normal smallintestine


10

WHIPWORMSTrichuris vulpis

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11

WHIPWORMSTrichuris vulpis

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➤

Infective eggs hatch tolarvae and mature to adultworms in 74 to 87 days in

the cecum.

Mature wormspass eggs inthe feces.

Infective larvae develop in 2to 4 weeks within the egg.

The dog ingestsinfective eggs found in soil.

WHIPWORM WHIPWORM INFECTION

➤

Normal cecumand the ileocecal

junction of thesmall and

large intestine

➤

Infected cecumwith numerous

whipwormsembedded in

the mucosa

➤Length of Life Cycle = 3 Months


12

ROUNDWORMSToxocara canis*, Toxocara cati*, and Toxascaris leonina*

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➤

Adult roundworms livein the small intestine.

ROUNDWORMS

➤

Roundworms maybe transmitted toyoung animals in utero or via milk(except T. leonina).

Eggs are passedin the feces.

Toxascarisleonina egg

Toxocaracanis egg

Toxocaracati egg

Infective eggs develop in the environment:approximately 1 week for Toxascaris sp. and 4 weeks for Toxocara sp.

The transport hostsingest infective eggs;larvae encyst in tissues.

The hosts ingest the infective eggs or thetransport host. Larvae of T. canis or T. catimay migrate extensively within the host’s

➤ ➤

13

ROUNDWORMSToxocara canis, Toxocara cati, and Toxascaris leonina

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ROUNDWORM INFECTION

➤

Small intestineinfected withroundworms

Length of Life Cycle = T. canis, approximately 4 to 5 Weeks; T. cati and T. leonina, =55 Days

➤

➤


* Larvae of both T. canis and T. cati may infect many organ systems in humans(visceral larva migrans); Toxascaris leonina is of no zoonotic significance.

˜


14

DIPYLIDIUM TAPEWORMSDipylidium caninum

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15

DIPYLIDIUM TAPEWORMSDipylidium caninum

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DIPYLIDIUM TAPEWORM DIPYLIDIUM TAPEWORM INFECTION

Tapeworm segmentscontaining egg packetsare passed in the feces.Occasionally, eggpackets are present infeces.

➤

➤

Eggs are ingestedby flea larvae.

Tapeworm eggsdevelop to infectivelarvae within thedeveloping flea.

Fleas are ingestedas the pet grooms.

➤

➤

Tapeworm larvae within the fleawill develop to adult tapeworms

in the small intestine.


➤

Smallintestineinfected

withtapeworms

➤

Length of Life Cycle = Approximately 3 Weeks

Dipylidium caninumegg packets containindividual eggs.

➤


17

TAENIA TAPEWORMSTaenia spp.

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16

TAENIA TAPEWORMSTaenia spp.

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Tapeworm segmentscontaining infective eggsare passed in the feces.Occasionally, eggs arepresent in feces.

➤

An intermediate hostingests the eggs.

The host becomesinfected by eating the

intermediate host➤


➤

Smallintestineinfected

withtapeworms

The eggs develop tolarvae in the tissues ofthe intermediate host.

➤Adult tapeworms develop

in the small intestine.

TAENIA TAPEWORM TAENIA TAPEWORM INFECTION


Eggs are released fromthe segments into theenvironment.

➤


18

GIARDIAGiardia spp.

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Trophozoites attach to themucosa of the small intestine

and may cause diarrhea.➤

Trophozoites usuallyform cysts that areintermittently passedin the feces.

Infective cysts are present in the environment.

Trophozoitesemerge from theingested cyst.

GIARDIA

19

➤

➤

Length of Life Cycle = 1 Week

EXTERNAL PARASITES20–21 Fleas

22 American Dog Ticks

23 Brown Dog Ticks

24 Deer Ticks

25 Common Ticks Compared

26 Ear Mites

27 Demodex Mites

28 Cheyletiella Mites

29 Sarcoptes MitesThe host ingestscysts from theenvironment,usually fromcontaminatedfood or water.


20

FLEASCtenocephalides felis

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FLEA

Adult flea remains on the dog or cat host,feeding and producing eggs.

Eggs fall off of thehost animal andhatch within 2 to 5days to larvae.

Larvae feed on adult fleafeces which fall off the hostand organic debris presentin the environment.

➤

Larvae developinto pupaeinside a debris-coated, silk-likefiber cocoon(cross section).

For each flea on the host, there are hundreds of eggs, larvae, and newly emerged adults, concentrated in the environment (carpet, bedding, soil, decaying vegetation, etc.).

Adult fleasemerge from

the cocoon insearch of ablood meal

➤

➤21

FLEASCtenocephalides felis

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FLEA ALLERGY DERMATITIS

Stage 1 Normal skin

Stage 2When a flea bites, it injects a

small amount of saliva into the skin, causing an inflammatory reaction

Stage 4Bacterial infection is a common sequela to

skin trauma caused by scratching.

Stage 3In animals that are allergic to the flea saliva,

the reaction is more pronounced, causingintense itching. Scratching may

cause increased inflammation and hair loss.➤

Length of Life Cycle = 2 Weeks to Many Months

➤


23

BROWN DOG TICKSRhipicephalus sanguineus

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AMERICAN DOG TICKSDermacentor variabilis

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AMERICAN DOG TICK

Engorged female ticks fall off the host and layseveral thousand eggs.

Engorged femalefeeding

➤

Eggs hatch to larvae.

Both larvae and nymphs

feed on smallmammals.

➤

Adult ticks attach to andfeed on dogs and wildlifesuch as raccoons.

Length of Life Cycle = 1 to 2 Years

Larvae feed, anddevelop to nymphs.

Nymphs feed anddevelop to adults.


Engorged female feeding

➤

Eggs hatch to larvae.Larvae and nymphsfeed on dogs andother small mammals.

BROWN DOG TICK

Adult ticks attach toand feed on dogs.

Larvae feed anddevelop to nymphs.

Nymphs feed anddevelop to adults.

Length of Life Cycle = 3 Months to 1 Year


25

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24

DEER TICKSIxodes scapularis (Syn. dammini)

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DEER TICK AMERICAN DOG TICK*


Engorged femalefeeding

Larvae feed on mice, the reservoir forLyme disease organisms.

➤

Adult ticks attach toand feed on dogs,white-tailed deer, and other animals.

Length of Life Cycle = 1 to 2 Years

Eggs hatch to larvae.

Larvae feed anddevelop to nymphs.

Nymphs feed on mice,wildlife, dogs, cats, andhumans, and develop toadults.

BROWN DOG TICK*

DEER TICK*➤

larvanymph

adult

engorged adult

larvanymph

adult

engorged adult

larvanymph

adult

engorged adult

COMMON TICKS COMPARED

* These ticks are found infrequently oncats and humans, but they do occur.


27

DEMODEX MITESDemodex canis

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DEMODEX MITE

Adult Demodex mite All developmental stagesoccur on the same host.

➤

Normal canine skin.Dogs normally have lownumbers of mites.

The entire life cycle of theDemodex mite occurs on the host.Mites are acquired by puppiesthrough intimate contact with theirinfested mother.

➤

Demodex mites live andreproduce in the hair folliclesand sebaceous glands.Increased numbers of mites areseen in animals with a geneticpredisposition or disorders ofthe immune system.

➤

Length of Life Cycle = 20 to 35 Days

26

EAR MITESOtodectes cynotis

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EAR MITE

Adult Otodectes cynotis mite

Normal feline earanatomy

Ear mites may be found onbody sites other than the earcanal. Animals becomeinfested by passive contactwith infested animals.

➤

Cat displays effects ofear mite infestation inthe ear canal—inflammation, redness,and swelling of canalstructures.

➤


➤


29

SARCOPTES MITESSarcoptes scabiei

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SARCOPTES MITE*

Adult Sarcoptes mite All developmental stagesoccur on the same host.

➤

Normal canine skin

Sarcoptes lesions often starton the elbows and earmargins. The disease ishighly contagious to otherdogs, cats, or humans.

➤

Sarcoptes mites tunnelin the skin causingintense itching.

➤

Length of Life Cycle = 17 to 21 Days

28

CHEYLETIELLA MITESCheyletiella yasguri, Cheyletiella blakei, and Cheyletiella parasitovorax

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CHEYLETIELLA MITES*

Adult Cheyletiella mite

➤

Normal canine skin

Cheyletiella mite infestationproduces hair loss, dullcoat, and dandruff.

Cheyletiella mites live onthe surface of the skinwhere they feed andreproduce. The mites arecontagious to otheranimals and can survivein the environment.

➤

➤


* Cheyletiella may cause papular eruptions inhumans. They do not reproduce on humans.

* Sarcoptes may produce severe transient pruritis inhumans but disease is usually self-limiting.


30

CANINE INTERNAL ORGANS

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FELINE INTERNAL ORGANS FELIN

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31

Trachea

Esophagus

Lungs Heart Liver Stomach Pancreas

Kidneys

Small Intestine

Large Intestine

Trachea

Esophagus

Lungs

Heart Liver Stomach Pancreas

Kidneys

SmallIntestine

Large Intestine


33

UNDER THE MICRO-34 Dirofilaria immitis

35 Alaria canisAleurostrongylus abstrusus

36 Ancylostoma spp.

37 Eucoleus (Capillaria) aerophilaEucoleus (Capillaria) boehmiDipylidium caninum

38 Giardia spp.

39 Isospora canisIsospora ohioensisIsospora felisIsospora rivoltaNeospora caninumParagonimus kellicotti

40 Physaloptera spp.Sarcocystis spp.Spirometra mansonoides

41 Strongoloides stercoralisTaenia spp.

42 Toxascaris leoninaToxocara canisToxocara cati

43 Toxoplasma gondiiTrichuris vulpis

44 Pearsonema (Capillaria) feliscatiPearsonema (Cappilaria) plica

45 Pseudoparasites

The egg of Toxocara canis is placed beside each parasite for scale.

Parasites Found in Blood

Parasites Found in Feces

Parasites Found in Urine

Pseudoparasites


PARASITES FOUND IN FECESU

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OSC

OP

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Aleurostrongylus abstrusus

First-stage larva of Aleurostrongylus abstrusus

35

Alaria canis

Egg of Alaria canis

Close-up of tail ofA. abstrusus

34

PARASITES FOUND IN BLOOD

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Dirofilaria immitis

Adult male heartworm with corkscrew-like tail is in center; adult female is on outside.

Single microfilaria of D. immitis (Difil® Filter Test)

Microfilaria of D. immitis (Difil® Filter Test) Anterior ends of microfilaria of Dipetalonemareconditum (left) and D. immitis (Modified KnottTest)



A. caninum

T. vulpis

U. stenocephala

Eucoleus (Capillaria) spp.


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37

Eucoleus (Capillaria) aerophila

Egg of Eucoleus (Capillaria) aerophila(respiratory tract)

Eucoleus (Capillaria) boehmi

Egg of Eucoleus (Capillaria) boehmi(nasopharynx)

Surface of eggof Eucoleus(Capillaria)boehmi

Dipylidium caninum

Dipylidium caninum egg packetcontaining numerous eggs

36

PARASITES FOUND IN FECES

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Ancylostoma spp.

The egg of Ancylostoma caninum The egg of Uncinaria stenocephala

Fecal flotation preparationcontaining eggs of A. caninum,T. vulpis, U. stenocephala, andEucoleus (Capillaria) spp.

The egg of Ancylostoma braziliense The egg of Ancylostoma tubaeforme

Eggs of A. caninum and T. vulpis

The egg of A. caninum; oocysts ofIsospora canis

The egg of Toxocara canis is placed beside each parasite for scale.The egg of Toxocara canis is placed beside each parasite for scale.



ND

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39

Neospora caninum

Paragonimus kellicoti

Egg of the lung fluke Paragonimus kellicoti

Isospora canis

Oocysts of Isospora canis (left), I. ohioensis (top), and egg of T.canis

Isospora felis

Oocysts of Isospora felis Oocysts of Isospora felis (larger) andIsospora rivolta (smaller)

Oocysts ofNeospora caninum(arrows)

Oocysts ofIsospora felis(smaller), and egg ofToxocara cati

38


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Giardia spp.

Cyst of Giardia spp. (Sheather’s sucroseflotation)

Cysts of Giardia spp. (zinc sulfate flotation, iodine stain)

Stained trophozoite ofGiardia spp. (fecalsmear)

Close-up of cysts of Giardia spp. (zinc sulfate flotation, iodine stain)

Isospora felis, Isospora rivolta




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41

Strongyloides stercoralis

First-stage larvae of Strongyloides stercoralis

Anterior end ofStrongyloidesstercoralis

Taenia spp.

Egg of Taenia spp. Eggs of Echinococcus spp. are similar, and thus are not easily differentiated from those of Taenia spp.

Ruptured egg of Taenia spp.Note the exposedhexacanth embryo.

40


UN

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E MIC

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SCO

PE

Physaloptera spp.

Egg of Physaloptera spp.

Sarcocystis spp.

Sporocytes of Sarcocystis spp.

Spirometra mansonoides

Egg of the tapeworm Spirometra mansonoides




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OSC

OP

E

43

Toxoplasma gondii

Oocysts of Toxoplasma gondii

42


UN

DER

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RO

SCO

PE

Toxascaris leonina

Egg of Toxascaris leonina

Toxocara canis

Eggs of Toxocara canis

Toxocara cati

Egg of Toxocara cati

Surface of egg ofToxocara cati

Eggs of Toxocara canis,Toxascaris leonina,and Ancylostomacaninum

Trichuris vulpis

Egg of Trichuris vulpis



PSEUDOPARASITESU

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OSC

OP

E

45

Soil fungus—Common fecalpseudoparasite

Hair, air bubble, and flea egg—fecal pseudoparasites

Egg of rodent tapeworm—appears in feces as result of pre-dation

Mite egg—fecal pseudoparasite

Sporocysts of Monocystis orRhyncocystis (earthworm parasites)—appears in feces asresult of ingestion

Pine pollen—fecal pseudopara-site

Tree pollen—fecal pseudopara-site

Plant hair—fecal pseudoparasite

Grain mite and air bubble—fecal pseudoparasites

Yeast—fecal pseudoparasite

44

PARASITES FOUND IN URINE

UN

DER

TH

E MIC

RO

SCO

PE

Pearsonema (Capillaria) feliscati

Egg of Pearsonema (Capillaria) feliscati

Egg of Pearsonema (Capillaria) plica


Surface of eggof Pearsonema(Capillaria)feliscati


pfizer atlas of veterinary clinical parasitology...veterinary clinical parasitology isbn...

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