Metastrongylus

Lungworms of Pigs

METASTRONGYLUS species

• Found in the bronchioles and smaller bronchi.
• Three species, but these are all very similar.
• Look like the Dictyocaulus species in ruminants and produce similar pathology.
• Very pathogenic and can cause severe lung damage.
• Even low level infections will check growth.
• Immunity develops quickly.
• Larvated eggs with a wavy outline passed in faeces.
• Intermediate host is the earthworm, therefore this only affects outdoor pigs.
• Becoming more common with the trend towards free-range husbandry.
• Infection occurs when the earthworm is eaten.
• Larvae migrate via the mesenteric lymph nodes to the lungs.

• Found in bronchioles and smaller bronchi
• Grossly:
  • Small grey nodules, especially along ventral border of caudal lobes
  • Adult worms in bronchi and bronchioles
• Histologically:
  • Catarrhal and eosinophilic bronchitis and bronchiolitis
  • Possibly atelectasis
• Rarely becomes extensive
• May transmit swine influenza