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15 Cards in this Set

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Genera of Trichostrongyles found in the abomasum



Trichostrongylus (axei)

Common name and main hosts of Haemonchus genus

Barber's pole worm

Sheep, cattle, deer, camel

Haemonchus species

H. contortus

H. placei

Which species occurs in sheep (and rarely cattle)

H. contortus

Which species occurs in cattle (and rarely sheep)

H. placei

Hosts and location of Haemonchus



Features of genus Haemonchus

2-3 cm long (largest in abomasum)


Tooth in buccal capsule

Prominent cervical papillae

"Barber's pole" in female

Female with large vulval flap

Asymmetrical dorsal ray

Spicules with barbs

Life cycle of Haemonchus


L3 burrows in between abomasal glands and moults to L4

Re-emerge to lumen

Pre patent period of Haemonchus

21 days

Effects on host of Haemonchus

L4 and adult feed on blood

Ingest 0.05ml/worm/day

Microcytic, hypochromic anaemia

Hypoproteinaemia: bottle jaw

Do not cause diarrhoea

Reduced exercise tolerance

Heavy infections: sudden death

Voracious blood sucker

Epidemiology of Haemonchus

High biotic potential (5-10,000 eggs/day)

Eggs will not hatch below 10 degrees

Larvae not resistant to desiccation

Haemonchus in summer rainfall areas

Increase in spring, maximum in february then decline

Overwinter as hypobiotic larvae

Haemonchus in winter rainfall areas

Summers too hot and dry, winter too cool

Develop in spring and autumn

Problems in spring lambs and autumn lambing ewes

Immunity towards Haemonchus

Self cure when threshold reached

Resulting immunity is labile

Do not always get strong immunity to reinfection after self-cure

Vaccine for Haemonchus


Claim to have 75-95% protection used along with antihelmintics