Species, Distribution, Identification & Life cycle of Haemonchus

Haemonchus

·         This is a blood sucking abomasal nematode may be responsible for extensive losses in sheep and cattle especially in tropical areas.

·         Host: Cattle, Sheep and goat

·         Site: Abomasum

                                

Species:
Haemonchus contortus	Sheep and goat	Recently, considered the same species for sheep and cattle
Haemonchus placei	Cattle
Haemonchus similis	cattle

                                   

Distribution:

• Worldwide; mostly important in tropical and subtropical areas

           

Identification:

o Gross:

§  Larger in size, 2.0-3.0cm

§  In Fresh specimen, the white ovaries winding spirally around the blood filled intestine of parasite produced a ‘Barbar pole’ appearance.

o Microscopic:

§  The male has a asymmetrical dorsal lobe and barbed spicule

§  The female has vulvar flap except H. placi

§  In both sexes, there are cervical papillae and a tiny lancet (For puncture of intestinal vessel/mucosal vessel) inside the buccal capsule.

Life Cycle:

·  Direct

o   Infective stage L₃

o   Female are prolific egg layers

Eggs are passed in the faeces

The eggs hatch to L₁ on the pasture

L₃ is developed

After ingestion, exsheathment occurred in rumen

 

Larva moult twice in close association to gastric gland. Just before the final moult (L₄-L₅), the piercing lancet is developed which enables them to obtain blood form mucosal vessel

As adult, they move freely on the surface of the mucosa

PPP: 2-3 weeks for sheep

            4 weeks for cattle