Nematodirus in sheep

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Nematodirus in sheep

Identify adult teladorsagia circumcincta, trichostrongylus spp, cooperia spp, haemonchus spp, Nematodirus battus + other nematodirus spp. Identify trichostrongyle eggs + differentiate them from nematodirus spp eggs

N. battus

Affects lambs

Cold/temperate countries

SI

Morphology

2cm

Found tangled - cotton wool like

Cephalic vesicle

Long thin spicules- M

cf cooper

Large eggs - F

Eggs

150 um

Brown colourisation

cf

Parallel sides

Demonstrate a deep knowledge of life cycles of nematodirus battus + other nematodirus species

N. baths life cycle

Unembryonated eggs shed in faeces

L1-malt->L2-malt-> L3

Within egg

cf

L3 hatches

L3 infective

L3 ingested

L3->L4

Lumen of SI

L4 burrows into mucosa

L4->L5

L5 emerges

Matures in SI

PPP = 15 d

Demonstrate a deep understanding of the epidemiology of nematodiriasis battus

L3 develops in egg over summer

Overwinters as egg

cf

Hatching requirements

Exposure to prolonged chill

Exposure mean day/night temp 10 deg C

(Weather)

L3 emergence en masse in spring

For disease to occur

Hatching co-incide w susceptible lambs

Old enough to graze

B4 immunity

May-June in 4-12 week old lambs

Ewes unaffected

Little affect on disease

Lamb to lamb cycle

Use same pastures for lambs year on year INC risk

Disease not necessarily seen every year

Changes?

Climate change

Seen in autumn also

Understand pathogenesis of disease associated with nematodirus spp infections in sheep

Pathology

L5 destroy mucosa

Catarrhal enteritis

Villous atrophy

Absorption disrupted

Small numbers cause disease

2000

Influences epi

cf

Mobidity - 100%

Mortality up to 20%

Clinical signs

Explosive acute watery diarrhoea

Dec appetite

Dehydration

Abdo pain

Weight loss

Lambs 4-12 weeks

cf

Disease b4 PPP

Mean WEC > 500 e/g = heavy infestation

cf

Low

Diagnosis

May - June

Grazing history

Age of lambs

Clinical signs

Control

Grazing management

Prophylactic Tx

April - June

NOT susceptible to injectable MLs

Disease forecasting