Metastrongylus

Lungworms of Pigs

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