Parasitology > Ruminant Strongyles > Flashcards

Ruminant Strongyles Flashcards

(46 cards)

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1
Q

Ruminant strongyle classification

A 
Phylum: Nematoda
Order: Strongylida
Superfamily: Trichostrongyloidea
Family: Trichostrongylidae
- Ostertagia
- Haemonchus
- Trichostrongyles
- Cooperia 
Family: Molineidae
- Nematodirus
Superfamily: Strongyloidea
Family: Chabertiidae
- Oesophagostomum
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2
Q

General Strongyle life cycle

A

DH has PPP of 2-4 weeks
- diagnostic stage: eggs, hatch; L1 emerges –> environment –> 1st molt –> L2 –> 2nd molt –> L3 (parasitic stage) –> 3rd molt –> migration in host –> L4 (4th molt) –> adults –> copulation

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3
Q

Periparturient rise

A

Relaxation of immunity due to increases in prolactin

- rise in nematode egg counts in the feces of lactating ewes or does at weaning

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4
Q

Which species of Trichostrongylidae has the longest PPP?

A

Haemonchus placei

- 23-32 days

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5
Q

Which species of Trichostrongylidae only infects horses?

A

Haemonchus axei

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6
Q

What species of Chabertiidae has the longest PPP?

A

Oesophagostomum radiatum

- 28-41 days

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7
Q

What species of ruminant strongyles lives in the large intestine?

A

Oesophagostomum radiatum

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8
Q

Trichostrongyles

A

Common, high significance

  • primarily ruminants
  • few species in horses and swine
  • parasitic gastroenteritis (PGE) = any GIT problem due to parasites, common name
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9
Q

Parasitic gastroenteritis

A

Subclinical disease has dramatic production losses

  • significant weight loss
  • diarrhea (watery, green)
  • loss of appetite
  • high proportion of animals affected
  • dehydration
  • rough hair coat
  • submandibular edema
  • pale mucous membranes
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10
Q

Arrested larval development (ALD)

A

Hypobiosis

  • larval development stops at a specific stage –> undergo no further growth
  • slow metabolic rate
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11
Q

Influencing factors of hypobiosis

A
  • seasons
  • climate
  • host immune responses
  • overcrowding effects in parasite population
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12
Q

Diagnosis of PGE

A

History: grazing, parasites present, seasonal occurrence

Clinical signs: pathology, fecal egg counts

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13
Q

Control of PGE

A

Consider epidemiology of parasites being targeted

  • biology of parasite populations
  • climate
  • pasture management
  • animal management
  • properties of drug being used
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14
Q

Anthelmintic resistance

A

FDA-approved antiparasitic drugs for sheep and goats

  • huge problem in small ruminant strongyles, emerging problem in cattle
  • detection: fecal egg count reduction test, larval development assays
  • FAMACHA test for anemia
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15
Q

Refuge

A

Susceptible parasite gene pool not exposed to a particular control measure (escapes selection for resistance)

  • pasture
  • untreated animals
  • inhibited larvae
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16
Q

Integrated pest management

A
  • fecal egg count: eggs per gram
  • pasture rest/rotation
  • multi-species grazing
  • increasing grazing height
  • reducing stocking rates
  • resistant breed selection
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17
Q

FAMACHA test

A

Anemia guide

  • allows for fewer anthelmintic treatments
  • monitor fecal egg counts (over dispersal of parasites)
  • done in small ruminants, especially for Haemonchus contortus
  • deworm on individual basis instead of the whole herd
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18
Q

Ostertagia ostertagi

A

Most important one in cattle!!

  • site of adults: abomasum
  • PPP: 18-21 days
  • family: Trichostrongylidae
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19
Q

Ostertagia ostertagi - L3 stage

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A

Burrow into gastric glands in pyloric and fundic regions

  • molts 2 more times
  • emerges as immature adults
20
Q

Ostertagia ostertagi - life cycle

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A

Adults; no feeding –> eggs in feces (diagnostic stage) –> L1 –> L2 –> L3 (infective stage) –> L3 burrow gastric glands, pyloric/fundic regions –> L4 ALD abomasal glands –> emerge as immature adults

21
Q

Ostertagia ostertagi - pathology

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A

PPP: 18-21 days

- can arrest as early L4 stage in abomasal glands

22
Q

Ostertagiosis

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A

Type 1
- occurs when recently ingested L3 develop to adulthood without ALD
- young cattle grazing pasture for first time
Type 2
- when arrested larvae synchronously resume development, synchronous emergence from glands weeks or months after infective L3 are ingested
- animals 2-4 years of age

23
Q

Ostertagia commonly arrest when it is ______

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A 
Hot outside (March-September) for southern states = large number of adults in fall
October - March in Northern states = large number of adults in summer
24
Q

Ostertagia pathology is associated with _______

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A

Larval growth and development

- NOT feeding behavior!!

25
Ostertagiosis - clinical signs
- diarrhea - weight loss/emaciation - dehydration/thirst - hypoproteinemia/submandibular edema
26
Teladorsagia circumcincta
Sheep and goats (same as O. ostertagi, just different host) - abomasum - contributor to PGE - diarrhea, poor weight gain/weight loss - cool dry conditions
27
Haemonchus - life cycle
Eggs in feces (diagnostic) --> L1 --> L2 --> L3 (infective) --> L3 exsheath in rumen --> L3 move to abomasum, near glands --> L4 ALD, emerge immature adults, blood feeders --> molt to adults, blood feeders!!
28
Haemonchus classification
Family: Trichostrongylidae - H contortus: sheep, goats - H placei: cattle
29
Haemonchus - L3 stage
Pasture L3 are not resistant to cold! - exsheath in rumen - move to abomasum near glands - molt 2 more times - emerge as immature adults - blood feeders! - can arrest
30
Haemonchosis - clinical signs
Hyperacute, acute, chronic - anemia - skin pallor - pale mucous membranes - hypoproteinemia and edema (bottle jaw) - dark feces - death - blood feeders as adults and L4s
31
Trichostrongylus spp.
Family: Trichostrongylidae - T. axei: abomasum in ruminants, stomach in horses - T. colubriformis: SI in ruminants - asymptomatic, contributor to PGE; ALD - massive infections = black scours
32
Which is larger among Trichostrongylus, Ostertagia, or Haemonchus?
Haemonchus
33
Cooperia classification
``` Family: Trichostrongylidae Cattle - C. onchophora - C. punctata - C. pectinata Cattle and sheep - C. sumabada Sheep and goats - C. curticei ```
34
Cooperiosis
Small intestine, can arrest (ALD) - secondary pathogens - weight loss/poor weight gain - diarrhea
35
Oesophagostomum classification
Family: Chabertiidae Cattle: Oesophagostomum radiatum Sheep and goats: O. columbianum
36
Morphology of Oesophagostomum radiatum
Cuticular modifications at the anterior end - cephalic vesicle - cervical vesicle - cervical alae
37
Oesophagostomum - life cycle
Eggs in feces --> L1 --> L2 --> L3 (infective) --> L3 exsheath in SI mucosa; form nodules --> emerge from tissue to lumen as L4 --> L4 move to colon/cecum; emerge as adults
38
Oesophagostomum pathology
- hemorrhagic or purulent nodules - mucus - leakage of blood and plasma proteins - contributes to PGE: inappetence, weight loss, anemia, diarrhea
39
Diagnosis of ruminant strongyles
- culture and identify L3 - identify adults at necropsy - strongyle type eggs - fecal float: ellipsoid, thick shelled, greyish
40
Nematodirus classification
``` Family: Molineidae Cattle: N. helvetianus Sheep: - N. battus - N. filicolis - N. spathiger Found in temperate regions ```
41
Nematodirus spp
``` Pasture larvae - resistant to drying/freezing Eggs - very large Adults - cephalic vesicle: bulbous swelling of cuticle at tip of anterior end ```
42
Nematodirus - life cycle
Eggs in feces (diagnostic) --> larvae mature (L1-L3 in egg) --> hatch, extrinsic stimuli --> L3 (infective) --> L3 ingested, penetrate SI mucosa -->L3 --> L4 --> L4 enter lumen of SI --> molt to adults in SI
43
Nematodirus diagnosis
- fecal float - eggs: larger than typical "strongyle type" - ovoid to football shaped
44
What are the most important/least important cattle strongyles?
``` Most important - *Ostertagia ostertagi* - Cooperia - Haemonchus placei - Trichostrongylus axei Less important - Oesophagostomum - Nematodirus ```
45
What are the most important/least important small ruminant strongyles?
``` Most important - *Haemonchus contortus* - Trichostrongylus colubriformis - Teladorsagia circumcinta - Trichostrongylus axei Less important - Cooperia - Oesophagostomum - Nematodirus ```
46
Strategies for managing Haemonchus contortus
- specialized behaviors of goats - prefer to browse a variety of plants - accompanying physiological adaptations to consumption of secondary compounds contained in browse - browsing behavior - pasture management - bioactive forages - identifying and treating individual animals
Parasitology
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