Special Veterinary Pathology

HAEMONCHOSIS

Definition

• Under the family of Trichostrongyloidea, Haemonchus contortus is the worm seen in the abomasum of cattle, sheep and goat.

Pathogenesis

• They have direct life cycle
• The ingested larva mature in the abomasum and attach themselves to the mucosa and sucks blood
• By piercing the mucosa for blood they cause lacerations predisposing to gastritis

Clinical signs

• Anaemia is the most outstanding symptom and is associated with oedematous swelling under the jaw and ventral abdomen
• Diarrhoea with progressive weakness and emaciation results.
• Self cure phenomenon might occur due to the animal developing immunity.

Gross lesions

• Anaemia is manifested by pale mucous membrane and viscera.
• Abomasal mucosa reveals shallow ulcers and haemorrhages
• Ascites, hydropericardium and hydrothorax
• Hyperplastic changes in the bone marrow.

Diagnosis

• Symptoms
• Demonstration of ova