Ascariasis

The term Ascariasis refers to disease caused by nematode worms of the genus Ascaris. This disease can occur in a number of different species as described below.

In Pigs

Ascaris suum is the primary cause of ascariasis in pigs.

• 'milk spot' liver
• pigs
• common incidental finding at post mortem examination
• affected livers are condemned at meat inspection

Gross

• initial haemorrhagic tracts through the liver attributed to the migration of ascarid larvae
• later stages show fibrosis of these tracts as poorly defined, diffuse, white spots on the capsular surface

Microscopically

• initial haemorrhage and necrosis of parenchyma along the tracts
• later repair by fibrous tissue at foci
• inflammatory cell response contains many eosinophils, as well as lymphocytes and macrophages