Special Veterinary Pathology

BUNOSTOMIASIS

Synonym : Hook worm disease

Definition

• Hook worm disease of cattle, sheep and pigs caused by Bunostomum sp. present in the small intestine characterized by poor growth and blood loss with anaemia and anasarca.

Aetiology

• Bunostomum phlebotomum -Cattle
• Bunostomum trigonocephalum –Sheep

Incidence

• Calves 4-12 months of age are most commonly affected and it is more in winter months

Life cycle

• Life cycle is direct
• The egg hatch and larva is produced.
• The larvae enter through the skin and also through the mouth.
• After skin penetration, enter the blood stream
• Then carried to the heart, lungs, enter the alveoli where the fourth stage larvae develop
• The larvae moved to the pharynx, are swallowed and reach intestine
• The larvae then penetrate the intestinal wall and return to its lumen without further migration
• The prepatent period of B.phlebotomum is about 8 months

Pathogenesis

• Hookworms are blood suckers and cause severe anaemia
• More number of worms are present may cause death in young cattle
• Hypoproteinaemic oedema and mild or intermittent diarrhoea

Clinical signs

• Constipation, unthrifty and anaemia
• In severe infestations, pale mucous membrane, anasarca under the jaw and along the belly, prostration and death in 2 to 3 days in cattle

Gross lesions

• Worms are found in the first few feet of the small intestine
• Deeply blood stained intestinal contents
• In calves, 100 or more worms present in the intestine, suggest a significant level of infestation
• Over 2000 worms, indicates degree of infestation likely to be fatal

Diagnosis

• Demonstration of blunt ends and deeply pigmented embryonic cells of hookworm eggs in the faeces