Endoparasites (year 2) Flashcards by Kai Sainsbury

name the species of nematode found in the abomasum of sheep?

Teladorsagia circumcincta
Trichostrongylus axei
Haemonchus contortus

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name the abomasal worms of sheep from largest to smallest

Haemonchus contortus (largest)
Teladorsagia circumcincta
Trichostrongylus axei (smallest)

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how large is Haemonchus contortus?

20-30mm (females larger)

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what is Haemonchus contortus also known as?

barber pole worm

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why is Haemonchus contortus known as the barber pole worm?

red gut wraps the white ovaries

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what are the defining features of the male Haemonchus contortus?

dorsal lobe of bursa is small and asymetrical

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what abomasal worms have cervical papillae?

Haemonchus contortus

Teladorsagia circumcincta

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describe the cervical papillae of Haemonchus contortus

prominent

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describe the cervical papillae of Teladorsagia circumcincta

tiny

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which worms of the abomasum have vulva flaps?

Haemonchus contortus

Teladorsagia circumcincta

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what is the defining feature of male Teladorsagia circumcincta?

bursa with short spicules

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how long is Teladorsagia circumcincta?

10mm

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what colour is Teladorsagia circumcincta?

pink/brown

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how long is Trichostrongylus spp.?

5mm

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what is a distinct feature of Trichostrongylus spp.?

excretory notch

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what is the defining feature of male Trichostrongylus spp.?

short, stout, irregular spicules

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what is hypobiosis?

arrested development of larvae within the host in response to ambient drop in temperature and trigger from free living L3

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what is pre-patent period?

time between becoming infected and the detection of eggs in faeces

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what shape Teladorsagia circumcincta eggs?

barrel

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how long are Teladorsagia circumcinta eggs?

90micrometres

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what is the typical trichostrongyle lifecycle

worms mate in abomasum and produce eggs
eggs develop in faecal pat to L1
L1 hatches
feeds on bacteria in faeces
grows/moults to L2 then L3
L3 is dispersed by rain fall
grazing sheep ingest L3

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L3 in the typical trichostronyle lifecycle is ensheathed, what does this mean?

has 2 cuticles for protection

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what is the final stage of the lifecycle of Teladorsagia circumcincta?

L3 burrow into gastric glands
develops to L4 and L5
L5 emerge into the lumen
L5 mature to adults and lay eggs

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what is a patent infection?

one that can be detected

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when is hypobiosis in Teladorsagia circumcinta triggered?

late winter/early spring

how does Teladorsagia circumcincta cause disease?

emerging L5 damages the gastric glands | leaky mucous membranes

what is the function of the gastric glands?

maintain abomasal pH bacteriostatic convert pepsinogen to pepsin

what are the clinical signs of type one disease caused by Teladorsagia circumcincta?

``` watery diarrhoea weight loss/poor weight gain anorexia dehydration death ```

what animals is type one disease caused by Teladorsagia circumcincta seen in?

first season grazing lambs

what time of year is type I disease caused by Teladorsagia circumcincta seen?

mid summer onwards

what is type II disease of Teladorsagia circumcincta due to?

presence of hypobiosed larvae in abomasum - simultaneous L5 emergence

what animals is type II disease of Teladorsagia circumcincta seen in?

yearlings

what time of year is type II disease of Teladorsagia circumcincta seen?

late winter/early spring

what are the main species causing PGE?

Teladorsagia circumcincta Trichostrongylus spp. Cooperia spp.

where does L4 and L5 of Trichostrongylus spp. develop?

sub-epithelial teens in the deep mucosa

what does the development of L4 and L5 of Trichostrongylus spp. lead to?

villous atrophy haemorrhage oedema diarrhoea

what are the clinical signs of Trichostrongylus spp.?

black scour oedema weight loss/poor gain poor skeletal growth

what animals is Trichostongylus spp. seen in?

store lambs

what time of year is Trichostrongylus spp. seen?

autumn

what nematode species in the dose defining species for PGE?

Cooperia spp.

what is Cooperia spp. the dose defining species?

less susceptible to anthelminitics

what are the small intestinal nematodes?

Cooperia spp. | Trichostrongylus spp. Nematodirus battus

which of the small intestinal nematodes have a cephalic/cervical vesicle

Cooperia spp. | Nematodirus battus

how would the cephalic/cervical vesicles of Cooperia spp. and Nematodirus battus be described?

Nematodirus battus - bubble like | Cooperia spp. - small

what is the defining feature of male Cooperia spp.?

short, stumpy spicules

how long is Cooperia spp.?

10mm

how does Cooperia spp. appear?

coiled like a watch spring

how does Nematodirus battus appear?

white tangled groups (cotton wool)

what is the defining feature of male Nematodirus battus.?

long thin spicules

how large are Nematodirus battus eggs?

150micrometres

Cooperia spp. is a mild pathogen, what do heavy infections lead to?

catarrhal enteritis villous atrophy oedema diarrhoea

how long is Nematodirus battus?

20mm

which worm doesn't have a typical trichostrongyle lifecycle?

Nematodirus battus

describe the lifecycle of Nematodirus battus

``` unembryonated egg passes out into faeces L1 develops to L3 inside the egg then hatches L3 is ingested by animals burrows into SI mucosa L5 emerges from mucosa ```

how long is the pre-patent period of Nematodirus battus?

15 days

how long is the pre-patent period of typical trichostronyle lifecycles?

21 days

how does Nematodirus battus cause disease?

L5 destroys the mucosa leading to caterwaul enteritis and villous atrophy mean fluid/nutrient absorption is disrupted

what aged sheep is Nematodirus battus seen in?

4-12 weeks

what are the clinical signs of Nematodirus battus?

``` sudden acute watery diarrhoea dehydration abdominal pain anorexia weight loss ```

what triggers overwintered Nematodirus battus eggs to hatch?

prolonged periods of chill | mean temperature above 10

when is disease of Nematodirus battus seen?

May-June

what two factors need to occur for Nematodirus battus infection to occur?

hatching of eggs coincide with presence of susceptible lambs | lambs graze but don't have immunity

how is the Nematodirus battus cycle described?

lamb to lamb

where do larvae of Haemonchus contortus develop in the abomasum?

mucosa

what are the clinical signs of Haemonchus contortus?

anaemia oedema weight loss

when do outbreaks of Haemonchus contortus occur?

late summer

what is the main source of pasture contamination for Haemonchus contortus?

ewe - periparturient rise

why is the periparturient rise the main source of pasture contamination for Haemonchus contortus?

L3 do not survive the winter