Angiostrongylus vasorum

ANGIOSTRONGYLUS VASORUM

• Infects dogs and foxes.
• A typical metastrongyloid, with the adult worms living in the pulmonary arteries and the right side of the heart.

Life-Cycle

Adults (approximately 2cm), produce anticoagulants to reduce thrombus formation leading to coagulation disorders:

→ eggs laid into pulmonary arteries

→ trapped in lung capillaries

→ larvae (with merastrongyloid kinky tail) hatch out

→ alveoli (causing a small injury)

→ trachea

→ swallowed

→ passed in faeces

→ slug (intermediate host)

→ eaten by dog or fox (final hosts)

→ larvae migrate via mesenteric lymph nodes

→ blood stream

→ heart.

Epidemiology

Once restricted to Southern Ireland and Cornwall, this lungworm is spreading across the British Isles and is now endemic in the South-East. The fox may act as a reservoir of infection.

Angiostrongylosis

• Clinical signs of angiostrongylosis are associated with:
  • accumulating lung damage caused by eggs and larvae (respiratory distress)
  • coagulation disorders caused by adult worms (bruising, haematomas, e.g. in spinal cord)
• Diagnosis: demonstration of large numbers of L1 in faeces (with Barmann technique).

Treatment of Lungworms in Dogs and Cats

• Angiostrongylus vasorum is easy to treat with suitable anthelmintics, but the others require high daily doses of benzimidazoles for 3-7days.
• Two or more courses of treatment may be necessary (with a rest period between each).

• Adult worms live in the pulmonary arteries and right side of the heart dogs and foxes
• Cause a proliferative endoarteritis
• More severe damage is caused however by eggs lodging in arterioles and capillaries
• In severe infection, this can result in pneumonia and pulmonary oedema as an acute syndrome
• Circulatory impedance can result in congestive cardiac failure
• Particularly a problem if dogs eats snails
• Gross:
  • Patchy white appearance with haemorrhagic areas within
• Microscopically:
  • Golden pigment within macrophages (haemosiderin)
  • Inflammation and scarring of alveolar walls -> enlargement of remaining air spaces
• Worms secrete anticoagulant -> haemorrhage in other parts of body
• May present as neurological cases due to the haemorrhage
• May cause pulmonary thromboembolism