Angiostrongylus vasorum

Also known as:

Haemostrongylus vasorum

Scientific Classification

Kingdom	Animalia
Phylum	Nematoda
Class	Secernentea
Order	Strongylida
Family	Metastrongylidae
Genus	Angiostrongylus
Species	A. vasorum

Hosts

Definitive host: Dogs and foxes. Intermediate host: Mainly snails and slugs.

Identification

The adults are slender, and measure around 2cm in length. The males have a small bursa.

Life Cycle

The adults are ovo-viviparous. The adults lay eggs in the pulmonary arteries. The eggs then hatch in the capillaries. The first stage larvae migrate into the alveoli and then the trachea. They are swallowed, enter the intestinal system and are then past in the faeces. The intermediate host then become infected, which later infect the definitive host.

The larvae the develop into the definitive host, and migrate via the mesenteric lymph nodes, and the blood where they affect the heart, primarily the right ventricle.

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