Nematode I Flashcards
(99 cards)
1
Q
Ascarids
– Superfamily Ascaridoidea
Brief Description
A
Ascarids, very common intestinal large roundworms.
*often just called roundworms.
*some of the largest known.
*several inches up to 2 feet! Zoonotic
2
Q
Ascarids
– Superfamily Ascaridoidea
Common in?
A
Dogs, cats, pigs, cattle, horses, chickens, and other animals.
*most frequently found in young animals.
3
Q
Ascarids
– Superfamily Ascaridoidea
Direct or indirect life cycle?
A
Direct.
-transmitted by ingestion of egg by a new host.
4
Q
Ascarids
– Superfamily Ascaridoidea
Where are they in the host?
A
Juvenile stages are not confined to the intestinal lumen (invade other tissues).
*often feature migration within the host.
5
Q
Ascarids
– Superfamily Ascaridoidea
What do males have?
A
Curved tails.
6
Q
Ascarids
– Superfamily Ascaridoidea
General Life Cycle
A
- Eggs are very resistant.
- Eggs contain J1 when excreted in feces.
- Juveniles develop into J2 in egg.
- New host ingests infective eggs.
- Eggs hatch in host intestines.
- Juveniles burrow through intestinal wall and enter bloodstream.
- Travel to other parts of the body to further develop.
- Eventually make their way back to intestines where adults form and produce eggs.
- Eggs excreted in feces.
7
Q
Ascarids
– Superfamily Ascaridoidea
Eggs are….?
A
- Found in fecal polluted soil.
- Can survive and remain infective in soil for many years.
- Eggs are infective.
8
Q
Ascarids
– Superfamily Ascaridoidea
What is usually the infective stage?
A
The J2 in egg.
9
Q
Ascarids
– Superfamily Ascaridoidea
Ascaris suum is the?
A
Intestinal roundworm of pigs, and the most common parasite found in pigs.
*more common in pigs less than 1 year.
10
Q
Ascarids
– Superfamily Ascaridoidea
Ascaris suum
Parascaris equorum
Toxocara canis
Toxocara cati
Life Cycle
A
- Eggs containing J1 excreted in feces.
- Eggs containing J3 ingested by new host.
- Eggs hatch in intestine and travel to liver.
- J3’s go from the liver to the lungs.
- Travel up the bronchial tree to pharynx and are swallowed.
- Mature to adults in the small intestine (produce eggs).
- Eggs excreted in feces. Process takes 6-8 weeks (prepatent period)
11
Q
Ascarids
– Superfamily Ascaridoidea
Ascaris suum
What type of migration do they have?
A
Hepato-trachael larval migration.
12
Q
Ascarids
– Superfamily Ascaridoidea
Ascaris suum
Parascaris equorum
Symptoms
A
- Poor growth.
- Coughing (hemorrhagic lesions in lungs).
- Milk spots on the liver.
- Intestinal or bile duct blockage (due to adults)
13
Q
Ascarids
– Superfamily Ascaridoidea
Ascaris suum
What happens to the milk spots on the liver, why are they important?
A
They will eventually go away. They are important because they are a reason for meat condemnation.
14
Q
Ascarids
– Superfamily Ascaridoidea
Ascaris suum
What causes the most damage to the host?
A
Larval migrations.
15
Q
Ascarids
– Superfamily Ascaridoidea
Ascaris suum
Parascaris equorum
Diagnosis
A
Eggs in feces, will NOT see them during the prepatent period.
16
Q
Ascarids
– Superfamily Ascaridoidea
Ascaris suum
Parascaris equorum
What do the eggs look like?
A
- Oval and thick shelled.
- Rough, sticky, external surface.
*very highly resistant to standard disinfectants.
17
Q
Ascarids
– Superfamily Ascaridoidea
Ascaris suum
Parascaris equorum
Prevention
A
Regular deworming does help, but it does not totally prevent.
18
Q
Ascarids
– Superfamily Ascaridoidea
Parascaris equorum
Brief Description
A
Large conspicuous roundworm of horses.
*females may be up to 50 cm (20”).
19
Q
Ascarids
– Superfamily Ascaridoidea
Parascaris equorum
What is the predilection site?
A
Small intestine of equines.
20
Q
Ascarids
– Superfamily Ascaridoidea
Parascaris equorum
Symptoms (especially in foals)
A
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
Q
Ascarids
– Superfamily Ascaridoidea
Toxocara canis
Brief Description
A
Common roundworm of dogs (especially puppies). Found rarely in cats.
22
Q
Ascarids
– Superfamily Ascaridoidea
Toxocara canis
Paratenic Hosts
A
Many mammals can serve as paratenic hosts. Especially mice and other rodents.
23
Q
Ascarids
– Superfamily Ascaridoidea
Toxocara canis
Prepatent Period
A
19-34 days!
24
Q
Ascarids
– Superfamily Ascaridoidea
Toxocara canis
How are animals infected?
A
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 (**H**eartworm **A**ssociated **R**espiratory **D**isease)
- 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.
