Day 1: Strongyle Flashcards

1
Q

What is the most important parasites in horses and the phylum name

A

Strongyles and the phylum is Nemathelminthes

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2
Q

Where are small and large strongyles located

A

Worldwide

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3
Q

Where are Strongyles located in the horse

A

Cecum and colon

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4
Q

What are the physical exam findings of a horse with Strongyles

A

Muscle Wasting
Thin
Poor hair coat
Depressed
Failure to grow

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5
Q

How do horses acquire Strongyles

A

Through grazing on infectious L3

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6
Q

What is the generalized Life Cycle of Strongyle

A

Direct life cycle-No intermediate host

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7
Q

How do large strongyles cause damage

A

By migrating larvae and adults “plug feeding”
Anterior ends of adults have large buccal capsules with teeth

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8
Q

What are the 3 types of Strongyles

A

Strongyle vulgaris
Strongyle edentatus
Strongyle equinus

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9
Q

What may Strongyle vulgaris look like

A

Large sized adult worms (2-3 inches)
Have teeth
Suck blood
May appear red in color

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10
Q

Explain the epidemiology of Strongyle vulgaris

A

Infective L3 are acquired on pasture during grazing
More common in young horses

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11
Q

What is the prepatent period of Strongyle vulgaris

A

6-7 months

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12
Q

Explain in detail the Strongyle Vulgaris life cycle starting with the ingestion

A

L3 is ingested and is in the SI and penetrates the intestinal wall where it molts into L4
L4 migrates upstream in artieroles within intima toward cranial mesenteric artery
L4 stays in cranial mesenteric artery for up to 120 days
L4 migrates from artioles to colon wall where it produces nodules
nodules rupture releasing larvae into lumen where they mature to the adult stage

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13
Q

How does the Large Strongyle migrate in the horse?

A

The horse GI tract folds back on itself allowing larvae to re-enter the GI tract by penetrating the cecal wall

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14
Q

What is the pathology of strongyle vulgaris

A

Creates occlusion of blood flow and block blood flow from the bowel
Artiel damage can lead to thromboembolism and reduce blood flow in the bowel
Arterial

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15
Q

What are the clinical symptoms of a horse with Large Strongyles

A

Colic-Due to decreased motility, secondary thromboembolic episodes
Rise in body temperature
Anorexia
Weight loss
Depression
Reluctance to move

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16
Q

How long is the prepatent period for Strongyle edentatus

A

11-12 months

17
Q

What is the Strongyle Edentatus lifecycle in detail

A

L3 is ingested and exsheaths in SI
L3 penetrates intestinal wall
L3 migrates to the liver via portal veins
L3 molts to L4 in liver
L4 stays in liver for 9 weeks
L4 migrates in abdominal connective tissue
L4 produces nodules in large intestine and ruptures releasing larvae into the lumen of the colon

18
Q

Where is the Strongyle edentatus located

A

Ceum and colon

19
Q

How long is the prepatent of Strongyle Equinus

A

9 months

20
Q

What are the clinical signs of S. edentatus or S. equinus

A

Low-grade fever
Inappetence
Depression
Diarrhea
Sometimes constipation/low fecal output
Abnormal gut motility can cause mild colic

20
Q

What is the detailed life cycle of Strongyle Equinus

A

L4 migrates along the peritoneum to the liver
L4 stays in the liver for 6-7 weeks
L4 emerges at the hepatic ligaments
L4 migrates in the pancreas and associated organs

21
Q

What is the pathology of S. edentatus or S. equinus

A

Infected horses have liver damage due to larval migration
migrating larvae are less pathogenic than S. vulgaris
Adults are attached to the mucosa and plug feed/suck blood

22
Q

What are small strongyle called

A

Cyathostomes

23
Q

What is the life cycle of small strongyle

A

Direct life cycle
L4 larval stage develops in the colonic mucosa, no tissue migration
Affect foals early because their prepatent period

24
Q

What is the prepatent period of small strongyles

A

6-10 weeks

25
Q

What is the pathology of small strongyles

A

Damage is caused by adult worms
L4 larvae in the large intestine
Less pathogenic than large strongyles because buccal capsule is smaller and there they take smaller bites

26
Q

What are the clinical signs of small strongyles

A

Large numbers of L4 larvae encysted in the colon wall
Severe colic
Diarrhea
Anorexia
Emaciation
Can be asymptomatic

27
Q

What is the treatment of small strongyle encysted larvae

A

Moxidectin, panacur

28
Q

Diagnosis of Equine Nematodes

A

Fecal flotation
Strongyle-type eggs
Cannot distinguish small and large strongyle infections
ELISA test used for S. vulgaris to detect migrating larval stages (Damage by L4s)

29
Q

Which environment favors large and small strongyles

A

Moist warm environment favors rapid development
More infective larvae produced and surviving, a shorter life cycle and higher worm burdens in the summer months

30
Q

When does transmission decline in small and large strongyles

A

Transmission declines as the temperature decreases in Fall and Winter
Dry periods in mid summer also kill L3 larvae on pasture

31
Q

What is the control of Equine GI parasites

A

PPPP
Permanent pasture promotes parasitism
Control pasture
Rotational grazing
Pasture sweeping
Plowing and reseeding