Small Ruminant GI Parasites Flashcards
1
Q
What are the common GI nematodes of small ruminants
A
- Haemonchus contortus
- Telodorsagia circumcinta (Ostertagia)
- Trichostrongylus axei
- Nematodirus spp
- Cooperia spp
2
Q
Who are most susceptible to GI nematode infections
A
- Young
- periparturient
- immuno-compromised
3
Q
What is the Life cycle of GI nematodes?
A
- Symbiotic/parasitic
- need host
- Contamination
- eggs
- Free-living
- L1 - L3 in fecal mass
- Infection
4
Q
What factors affect the magnitude of GIN contamination
A
- Stocking rate
- Age
- Periparturient
- Season
- Hypobiosis
5
Q
What is the pathogenesis of H. contortus
A
- Adults and L4 attach to abomasal mucosa
- consume a blood meal
- Pathogenic effect from:
- blood loss - anemia
- Abomasitis - impaired nutrient digestion
6
Q
What are the clinical signs of H. contortus infection
A
- Primary reflect anemia
- lethargy
- peripheral edema
- Pale mucous membranes
- PCV <15% (normal 25-45)
- Diarrhea
7
Q
What is the pathogenesis of Telodorsagia circumcincta?
A
- Type 1:
- L3 are ingested and enter into the parietal cell of the abomasum
- L3 ⇢ L4 and immediately ⇢ Adult worms which are released from the cell into the abomasal lumen where they produce eggs that are passed in the feces
- Abomasitis and protein losing gastropathy
- Type 2: Hypobiosis
- Same until L4 develops
- L4 enters parietal cell
- receive ‘hold up’ signal from environment
- L4 emergence w/ improved weather
- Release large numbers of immature adults ⇢ Abomasitis but no eggs in fecal
8
Q
What are the important intestinal Nematodes?
A
- Nematodirus
- Oesophagostomum
- Cooperia
- Ascaris sp
- Trichuris
9
Q
small ruminants
How are nematodes treated?
A
- Anthelmintic therapy - see chart
- Blood or plasma transfusion
- Iron/B-viamin supplementation
- TLC: low competition environment
- High quality nutrition
10
Q
What are the Principles for anthelmintic use in small ruminants
A
- ensure correct dose
- Use oral anthelmintics
- Withhold feed for 12-24 hrs
- Benzimidazoles and/or ivermectin
- Use combination of anthelmintics
- Avoid long acting dewormers
- Do not treat all animals
11
Q
What is the FAMACHA system?
A
- System of identifying anemic animals
- scoring the anemia and treating based on severity
- more pallor = greater worm burden
- Only appropriate for adult animals
12
Q
How does combination deworming work?
A
- Additive effect of each drug = increased efficacy
- Increased drug efficacy = fewer resistant worms
13
Q
What is a Fecal Egg Count Reduction Test (FECRT)
A
- sample 10-15 animals at the same time
- immediately prior to treatment
- 10-14 days after
- Calculate difference in egg #
- animals must have min of 150-200 epg before treatment
- Ideal reduction >90%
- reduction <70% suggests significant resistance to the dewormer
14
Q
What alternative treatments for GIN are there?
A
- Copper oxide wire particles
- cause cuticle defect in adult worms
- effect begins 12h post dose, and lasts 21 days
- Parasite inhibiting pants
- condensed tannins
- Nematophagus fungi
- Duddingtonia flagrans
- Pasture management
- Alternate species
- Good nutrition
- Genetic improvement
15
Q
What is Coccidiosis?
A
- Common disease of juvenile livestock
- usually subclinical
- Caused by Eimeria and Isospora sp
- NOT worms
