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Flashcards in Nematode I Deck (99):
1

Ascarids

-- Superfamily Ascaridoidea

Brief Description

Ascarids, very common intestinal large roundworms.

*often just called roundworms.

*some of the largest known.

*several inches up to 2 feet! Zoonotic

2

Ascarids

-- Superfamily Ascaridoidea

Common in?

Dogs, cats, pigs, cattle, horses, chickens, and other animals.

*most frequently found in young animals.

3

Ascarids

-- Superfamily Ascaridoidea

Direct or indirect life cycle?

Direct.

-transmitted by ingestion of egg by a new host.

4

Ascarids

-- Superfamily Ascaridoidea

Where are they in the host?

Juvenile stages are not confined to the intestinal lumen (invade other tissues).

*often feature migration within the host.

5

Ascarids

-- Superfamily Ascaridoidea

What do males have?

Curved tails.

6

Ascarids

-- Superfamily Ascaridoidea

General Life Cycle

1. Eggs are very resistant.

2. Eggs contain J1 when excreted in feces.

3. Juveniles develop into J2 in egg.

4. New host ingests infective eggs.

5. Eggs hatch in host intestines.

6. Juveniles burrow through intestinal wall and enter bloodstream.

7. Travel to other parts of the body to further develop.

8. Eventually make their way back to intestines where adults form and produce eggs.

9. Eggs excreted in feces.

7

Ascarids

-- Superfamily Ascaridoidea

Eggs are....?

1. Found in fecal polluted soil.

2. Can survive and remain infective in soil for many years.

3. Eggs are infective.

8

Ascarids

-- Superfamily Ascaridoidea

What is usually the infective stage?

The J2 in egg.

9

Ascarids

-- Superfamily Ascaridoidea

Ascaris suum is the?

Intestinal roundworm of pigs, and the most common parasite found in pigs.

*more common in pigs less than 1 year.

10

Ascarids

-- Superfamily Ascaridoidea

Ascaris suum

Parascaris equorum

Toxocara canis

Toxocara cati

Life Cycle

1. Eggs containing J1 excreted in feces.

2. Eggs containing J3 ingested by new host.

3. Eggs hatch in intestine and travel to liver.

4. J3's go from the liver to the lungs.

5. Travel up the bronchial tree to pharynx and are swallowed.

6. Mature to adults in the small intestine (produce eggs).

7. Eggs excreted in feces. Process takes 6-8 weeks (prepatent period)

11

Ascarids

-- Superfamily Ascaridoidea

Ascaris suum

What type of migration do they have?

Hepato-trachael larval migration.

12

Ascarids

-- Superfamily Ascaridoidea

Ascaris suum

Parascaris equorum

Symptoms

-Poor growth.

-Coughing (hemorrhagic lesions in lungs).

-Milk spots on the liver.

-Intestinal or bile duct blockage (due to adults)

13

Ascarids

-- Superfamily Ascaridoidea

Ascaris suum

What happens to the milk spots on the liver, why are they important?

They will eventually go away. They are important because they are a reason for meat condemnation.

14

Ascarids

-- Superfamily Ascaridoidea

Ascaris suum

What causes the most damage to the host?

Larval migrations.

15

Ascarids

-- Superfamily Ascaridoidea

Ascaris suum

Parascaris equorum

Diagnosis

Eggs in feces, will NOT see them during the prepatent period.

16

Ascarids

-- Superfamily Ascaridoidea

Ascaris suum

Parascaris equorum

What do the eggs look like?

-Oval and thick shelled.

-Rough, sticky, external surface.

*very highly resistant to standard disinfectants.

17

Ascarids

-- Superfamily Ascaridoidea

Ascaris suum

Parascaris equorum

Prevention

Regular deworming does help, but it does not totally prevent.

18

Ascarids

-- Superfamily Ascaridoidea

Parascaris equorum

Brief Description

Large conspicuous roundworm of horses.

*females may be up to 50 cm (20").

19

Ascarids

-- Superfamily Ascaridoidea

Parascaris equorum

What is the predilection site?

Small intestine of equines.

20

Ascarids

-- Superfamily Ascaridoidea

Parascaris equorum

Symptoms (especially in foals)

Similar to Ascaris suum, add:

-Death due to heavy infestation.

*from intestinal impaction or rupture.

*not that common.

-Reduced weight and appetite.

-Intermittent diarrhea, constipation, colic.

*after the parasite reaches adult.

21

Ascarids

-- Superfamily Ascaridoidea

Toxocara canis

Brief Description

Common roundworm of dogs (especially puppies). Found rarely in cats.

22

Ascarids

-- Superfamily Ascaridoidea

Toxocara canis

Paratenic Hosts

Many mammals can serve as paratenic hosts. Especially mice and other rodents.

23

Ascarids

-- Superfamily Ascaridoidea

Toxocara canis

Prepatent Period

19-34 days!

24

Ascarids

-- Superfamily Ascaridoidea

Toxocara canis

How are animals infected?

By ingestion of an egg, mostly by ingestion of a paratenic host. Often a mouse.

25

Ascarids

-- Superfamily Ascaridoidea

Toxocara canis

Predilection Site

Small intestine of dogs.

26

Ascarids

-- Superfamily Ascaridoidea

Toxocara canis

Symptoms in Adults

-Asymptomatic in adults with light infections.

-May be thin with a light coat.

27

Ascarids

-- Superfamily Ascaridoidea

Toxocara canis

Symptoms in Puppies

Puppies with heavy infections:

-Unthrifty

-Often pot-bellied

-Abdominal pain

-Diarrhea

-Vomiting

-Worms may be found in vomitus

-May cause death

28

Ascarids

-- Superfamily Ascaridoidea

Toxocara canis

Diagnosis

Eggs in the feces. Eggs are thick shelled and mammillated.

29

Ascarids

-- Superfamily Ascaridoidea

Toxocara canis

How is it transmitted from mother to pup?

In two ways:

1. Transplacental (major)

2. Transmammary (minor)

30

Ascarids

-- Superfamily Ascaridoidea

Toxocara canis

Prevention

Regular deworming works well. Dogs shouldn't get it.

31

Ascarids

-- Superfamily Ascaridoidea

Toxocara cati

Brief Description

Common roundworm of cats.

32

Ascarids

-- Superfamily Ascaridoidea

Toxocara cati

Differences from Toxocara canis.

1. Paratenic hosts more important cause of infection (cats hunt more).

2. No transplacental infection.

3. Transmammary infection is major route in kittens.

4. A wide range of common paratenic hosts.

*chickens, earthworms, cockroaches

5. Adult cats are more likely to get severe disease.

6. Often seen in vomitus.

33

Ascarids

-- Superfamily Ascaridoidea

Toxocara cati

Toxocara canis

Zoonosis, Two Diseases

Causes:

1. Visceral Larval Migrans (VLM)

2. Ocular Larval Migrans (OLM)

34

Ascarids

-- Superfamily Ascaridoidea

Toxocara canti

Toxocara canis

Visceral Larval Migrans

Larvae migrate through the human host's liver, lungs, heart, and brain. They cannot mature to adults in humans.

35

Ascarids

-- Superfamily Ascaridoidea

Toxocara canti

Toxocara canis

Visceral Larval Migrans, Symptoms

Depends on the number of larvae and the organs affected.

-Fever

-Myocarditis

-Eosinophilia

-Coughing

-Splenomegaly

-Abdominal Pain

-Itchy or pruritic rash

36

Ascarids

-- Superfamily Ascaridoidea

Toxocara canti

Toxocara canis

Visceral Larval Migrans, Treatment

Antihemitic drugs and anti-inflammatories. Will usually go away by itself since the worm cannot complete its life cycle in the human.

37

Ascarids

-- Superfamily Ascaridoidea

Toxocara canti

Toxocara canis

Ocular Larval Migrans

Toxocara invade the eye.

-Usually occurs in school aged children.

-Presents as eye pain and loss of vision.

-Results in retinal granulomas that are sometimes misdiagnosed as retinoblastoma resulting in unnecessary removal of the eye.

38

Ascarids

-- Superfamily Ascaridoidea

Toxocara canti

Toxocara canis

Zoonosis, How is it acquired?

Eggs are usually ingested from soil in an area where infected dogs or cats have defecated. Also the hair of an infected animal may contain infective eggs.

-Eggs become infective two weeks after excretion.

39

Pinworms

-- Superfamily Oxyuroidea

General Characteristics

1. Direct Life Cycles

2. Females have long, pointed tails.

*the reason they are called pinworms.

3. Have a realively low ability to migrate in host.

4. Common in many mammals, birds, reptiles, amphibians, insects.

*not found in dogs and cats

40

Pinworms

-- Superfamily Oxyuroidea

In what two animals do you NOT find pinworms?

Cats and Dogs.

41

Pinworms

-- Superfamily Oxyuroidea

Oxyuris equi

Breif Description

Pinworm of horses.

*found wouldwide in horses and donkeys.

*Females up to 15cm

*Males about 1 cm

42

Pinworms

-- Superfamily Oxyuroidea

Oxyuris equi

Predelicition Site

 

The large intestine in horses and donkeys.

43

Pinworms

-- Superfamily Oxyuroidea

Oxyuris equi

Life Cycle

1. Direct

2. Gravid (uterus full of eggs) female migrates to the anus of definitive host (horse/donkey).

3. Lays her eggs in yellowish-gray gelatinous material on perianal skin.

4. Femals then pass out of anus and die.

5. Juveniles develop inside egg to J3. (3-5 days)

6. Definitive host is infected by ingestion of infective egg.

7. J3's hatch in small intestine.

44

Pinworms

-- Superfamily Oxyuroidea

Oxyuris equi

Life Cycle, How long

It takes about 130 days to form mature gravid females, slow life cycle.

45

Pinworms

-- Superfamily Oxyuroidea

Oxyuris equi

What is the infective stage?

The J3 inside of the egg.

46

Pinworms

 

-- Superfamily Oxyuroidea

Oxyuris equi

How long is the prepatent period?

About 5 months.

47

Pinworms

-- Superfamily Oxyuroidea

Oxyuris equi

Basic Symptoms

-Due to egg laying habbits of the female.

-Causes an irritation in the anal and perianal area.

*very itchy

-Infected animals rub their hind ends frequently.

-Infected animals are restless and may loose appetite.

48

Pinworms

-- Superfamily Oxyuroidea

Oxyuris equi

What happens when infected animals rub their hind ends?

-Broken hair / rat-tailed apperance.

-Bare patches and inflammed skin on rump.

-Egg masses are very sticky and stick to fences, barn walls, mangers, etc to infect other horses.

*HIGHLY contagious.

49

Pinworms

-- Superfamily Oxyuroidea

Oxyuris equi

Diagnosis

1. Finding egg masses on perianal skin.

2. Eggs are oval with polar plug at one end.

50

Stomach Worms

-- Superfamily Spiruoidea / Habronematoides

General Characteristics

 

1. Stomach worm of horses.

2. Need an intermediate host (indirect life cycle).

*arthropod (fly)

3. Horses are definitive host.

51

Stomach Worms

-- Superfamily Spiruoidea / Habronematoides

Habronema spp.

Life Cycle

1. Eggs are excreted in feces.

2. Juveniles (larvae) hatch from eggs.

3. Juveniles are ingested from feces by fly maggots.

4. Juveniles develop to J3 in developing fly.

5. J3's migrate to mouth of fly.

6. Fly deposits the J3's on muzzle, eye, or cutaneous wound of horses.

7. Some are ingested by horse and mature into adult worms in the stomach of horse.

52

Stomach Worms

-- Superfamily Spiruoidea / Habronematoides

Habronema spp.

What happens when the horse ingests the eggs?

1. Juveniles in stomach mature into adults and mate and reproduce.

2. Eggs are prodcued in stomach and excreted in feces.

53

Stomach Worms

-- Superfamily Spiruoidea / Habronematoides

Habronema spp.

What happens when J3's are deposited into the eyes?

They cause ulcerative conjunctivitis.

*never mature into adults

54

Stomach Worms

-- Superfamily Spiruoidea / Habronematoides

Habronema spp.

What happens when J3's are deposited in wounds?

They cause granulomatous lesions.

*never mature into adults.

55

Stomach Worms

-- Superfamily Spiruoidea / Habronematoides

Habronema spp.

Symptoms, Adults in Stomach of Horse

-May be littel or no symptoms.

-May lead to gastritis or gastric tumors (in extreme cases).

56

Stomach Worms

-- Superfamily Spiruoidea / Habronematoides

Habronema spp.

Symptoms, Juveniles in Horses Eyes

-Form hard pus-filled nodules in eye.

-These must be surgically removed to prevent damage to the cornea.

*may have loss of vision.

57

Stomach Worms

-- Superfamily Spiruoidea / Habronematoides

Habronema spp.

Symptoms, Juveniles in Wounds

-Cause persistent cutaneous granulomas (pus filled).

*do NOT heal during fly season.

-Sores on skin are VERY itchy (prurulent).

*horses may injure themseleves trying to relieve itch.

-Larvae may be recovered from pus in granulomas.

58

Stomach Worms

-- Superfamily Spiruoidea / Habronematoides

Habronema spp.

What are other names for Cutaneous Granulomas?

-Cutaneous habranemiasis.

*iasis = infection from an arthropod.

-Swamp cancer.

-Summer sores.

59

Stomach Worms

-- Superfamily Spiruoidea / Habronematoides

Habronema spp.

Diagnosis

-Eggs in feces.

-Skin scraping of lesions may contain larvae.

60

Superfamily Trichuroidea

General Characteristics

Contains some very common parasites of domestic animals.

61

Superfamily Trichuroidea

Trichuris vulpis

Basic Description

-Whipworm of dogs, and very occasionally cats.

62

Superfamily Trichuroidea

Trichuris vulpis

Trichuris suis

Description of Adults

-3 to 8 cm

-Embed in intestine with whip end.

-Whip like in shape.

63

Superfamily Trichuroidea

Trichuris vulpis

Trichuris suis

Description of Eggs

-Lemon shaped.

-Plugs at opposite poles (bipolar plugs).

64

Superfamily Trichuroidea

Trichuris vulpis

Trichuris suis

Life Cycle

Direct Life Cycle

1. In egg, develops into a J1 in the environment.

2. Egg is very resistant.

*survives a long time in enviro - up to a year.

3. J1 in egg is infective stage.

4. Egg with J1 is ingested by host.

5. No migration in host body, mature in host intestines.

6. Adults in intestine produce eggs excreted in feces.

65

Superfamily Trichuroidea

Trichuris vulpis

Trichuris suis

Prepatent Period

About 3 months.

66

Superfamily Trichuroidea

Trichuris vulpis

Symptoms

-Most canine and feline infections are symptom free.

-May see an electrolyte imbalance.

-Heavy infections cause intermittent diarrhea with some mucus and blood, inflammation of cecum (typhitis).

67

Superfamily Trichuroidea

Trichuris vulpis

Trichuris suis

Diagnosis

Eggs in fecal flotation.

68

Superfamily Trichuroidea

Trichuris vulpis

Trichuris suis

Prevention

-Very hard to kill eggs in the environment.

-1% bleach, steam sterilization.

69

Superfamily Trichuroidea

Trichuris suis

General Description

Whipworm of pigs.

-Almost the same as Trichuris vulpis.

70

Superfamily Trichuroidea

Trichuris suis

Symptoms

-Especially in young pigs.

-Bloody diarrhea.

-Dehydration

-Anorexia

-Poor growth.

71

Superfamily Trichuroidea

Capillaria aerophila

Basic Description

Cat lungworm or bladderworm, fox lungworm.

72

Superfamily Trichuroidea

Capillaria aerophila

General Characteristics of Capillarids

-Very large, diverse group of worms parasitic in all classes of vertebrates.

-Always go after epithelial surfaces.

-In dogs and cats, can occur in airways, intestines, and bladder.

-Similar in morphology (eggs and adults) to Trichuris spp.

73

Superfamily Trichuroidea

Capillaria aerophila

Life Cycle

May be Direct, or may use earthworms as intermediate host.

1. Juveniles in eggs are ingested by host.

2. Migrate to lungs (sometimes bladder) and mature into adult worms.

3. Eggs are produced in lungs, swallowed, and excreted in feces.

74

Superfamily Trichuroidea

Capillaria aerophila

Symptoms

-Low grade infections in cats and dogs is most common

*causes a mild cough.

-Sometimes can cause high grade infection in cats, dogs (similar to foxes).

75

Superfamily Trichuroidea

Capillaria aerophila

Symptoms of High Grade Infection

-Wheezing and rattling respiration.

-Spells of coughing.

-Weakness, poor growth.

-May lead to death from bronchopneumonia.

76

Superfamily Trichuroidea

Capillaria aerophila

Diagnosis

Appear as small white nodules in lungs.

Eggs may be confused with Trichuris.

Eggs in:

-feces

-urine

-bronchial swab

77

Filaroids

Superfamily Filaroidea

Basic Description

-Cause of terrible human infections in the tropics (elephantiasis)

-MAJOR filaorid veterinary disease - hearworm.

78

Filaroids

Superfamily Filaroidea

General Characteristics

-Long white worms

*little distinguishing physical characteristics.

*large, up to 10 inches.

-Live in body cavities, tissue spaces, or the lymphatic system.

-All are transmitted by blook-sucking insects (mosquitoes)

79

Filaroids

Superfamily Filaroidea

Dirofilaria immitis (in dogs)

Basic Description

Canine Hearworm (also found in cats and ferrets).

-By far the most important filaroid parasite of domestic animals.

-Very common in dogs in U.S.

*most common in areas with salt marshes (mosquitoes).

-Atlantic, Gulf Coasts and some major rivers.

-up to 50% of dogs in these areas may be infected.

80

Filaroids

Superfamily Filaroidea

Dirofilaria immitis (in dogs)

What happens in human infection?

It is abortive, but can show up on x-ray and look like lung cancer.

81

Filaroids

Superfamily Filaroidea

Dirofilaria immitis (in dogs)

What does it inhabit in the animal?

It inhabits mosty the pulmonary arteries and right side of heart. It may also be carried to the lungs.

82

Filaroids

Superfamily Filaroidea

Dirofilaria immitis (in dogs)

Life Cycle

1. Uses mosquito as intermediate host (many types of mosquitoes).

2. Mosquito acquires the microfilaria (J1) while feeding on the definitive host (dog).

3. Develops into infective J3 in mosquito (1-4 weeks).

4. When mosquito bites another definitive host, the J3 infective larvae enter the new host's blood.

5. Mature into J5 in definitive host in about 2 months.

6. J5's develop into adults primarily in pulmonary arteries and right ventricle

*also brain, eye, other places.

7. About 5 months later, the adult females produce microfilaria which then enter the circulating blood of the definitive host.

83

Filaroids

Superfamily Filaroidea

Dirofilaria immitis (in dogs)

When are microfilaria first seen circulating in the blood?

6 to 7 months after initial infection.

-6 to 7 month prepatent period.

-Prepatent period is symptom free.

Adult worms can survive and reproduce for many years in heart of dog.

84

Filaroids

Superfamily Filaroidea

Dirofilaria immitis (in dogs)

Symptoms

-Appear at the same time microfilaria are seen in blood (6-7 mos post infection)

-Mostly due to blockage of pulmonary arteries and right ventricle.

-Fatigue

-Coughing

-Unthriftiness

-Eventually congestive hear failure and/or liver failure.

85

Filaroids

Superfamily Filaroidea

Dirofilaria immitis (in dogs)

Relationship of Worms (#) to Symptoms

-Dogs with less than 25: little or no disease.

-Dogs with about 50: moderate disease.

-Dogs with 100 or more: serious disease.

86

Filaroids

Superfamily Filaroidea

Dirofilaria immitis (in dogs)

Diagnosis

Many ways to diagnose.

1. Detection of microfilaria in circulating blood most common, old way.

2. Many serological tests are available (snap test).

3. Radiographs

87

Filaroids

Superfamily Filaroidea

Dirofilaria immitis (in dogs)

Diagnosis via Detection of Microfilaria in Blood

-Microfilaria are microscopic.

-25% to 50% of all infected dogs may not have detectable circulating microfliaria.

*adults live longer than microfilaria in host body.

88

Filaroids

Superfamily Filaroidea

Dirofilaria immitis (in dogs)

Diagnosis via Serological (Snap) Tests

-Much more accurate than microfilaria detection.

-Detect anitgens of worms or antibodies against worms.

-Capable of detecting heartworm infection during prepatent period.

-Before symptoms and/or microfilaria are present.

89

Filaroids

Superfamily Filaroidea

Dirofilaria immitis (in dogs)

Diagnosis via Radiographs

-Thoracic x-rays.

*right ventricular enlargement.

*only in severe cases.

-Echocardiograms

90

Filaroids

Superfamily Filaroidea

Dirofilaria immitis (in dogs)

Prevention

-Several effective preventive medications are available.

-All dogs in this part of the country should use preventive medication.

91

Filaroids

Superfamily Filaroidea

Dirofilaria immitis (in cats)

General Characteristics

-Same life cycle as in dogs.

-Cats are more naturally resistant than dogs.

*lower incidence of disease in cats.

*some cats immune systems may rid themselves of disease after infection.

92

Filaroids

Superfamily Filaroidea

Dirofilaria immitis (in cats)

Adult worms in cats?

-Live only about 2 years.

*compared to 5 to 7 years in dogs.

-Most infected cats only carry a few worms.

-Most worms never develop into adults.

*only 0% to 25%

93

Filaroids

Superfamily Filaroidea

Dirofilaria immitis (in cats)

In cats, microfilaria...?

May never be seen.

-production of microfilaria is inconsistent and short lived.

94

Filaroids

Superfamily Filaroidea

Dirofilaria immitis (in cats)

Pathology

-Adult worms damange the heart and lungs.

-Adult worms block and damage pulmonary arteries causing lungs to become hemorrhagic and edemic.

-Right sided heart failure may occure with high worm burdens (rare).

-Most damage occurs to the lungs.

-Severe lung inflammation and respiratory distress can result from infection with a single worm.

95

Filaroids

Superfamily Filaroidea

Dirofilaria immitis (in cats)

Symptoms (HARD)

HARD (Heartworm Associated Respiratory Disease)

-First stage of feline heartworm disease.

-Often misdiagnosed as asthma or bronchitis.

-When worms first enter pulmonary vessels.

96

Filaroids

Superfamily Filaroidea

Dirofilaria immitis (in cats)

Additional Symptoms

-Dyspnea

-Vomitting

-Lethargy

-Weight loss, loss of appetite.

-Often fatal in cats, may be sudden.

97

Filaroids

Superfamily Filaroidea

Dirofilaria immitis (in cats)

Diagnosis

-Similar to dogs, snap tests.

-Microfilaria testing is not useful.

98

Filaroids

Superfamily Filaroidea

Dirofilaria immitis (in cats)

Treatment

-Surgical removal.

-No satisfactory treatment is known.

-May cure itself spontaneously.

99

Filaroids

Superfamily Filaroidea

Dirofilaria immitis (in cats)

Prevention

There are several preventative medications available.