Changes

Antigens persist in the tissues, especially the joints, long after infection has resolved, stimulating '''auto-immune mechanisms''' which further damage the joints, causing damage which may be permanent.

Antigens persist in the tissues, especially the joints, long after infection has resolved, stimulating '''auto-immune mechanisms''' which further damage the joints, causing damage which may be permanent.

==Disease==

==Clinical signs==

The main presentation is as a chronic '''progressive polyserositis''' in pigs under 10 weeks old. '''Lameness and swollen joints''' are common and congenital arthrogryposis may be seen in young stock.

The main presentation is as a chronic '''progressive polyserositis''' in pigs under 10 weeks old. '''Lameness and swollen joints''' are common and congenital arthrogryposis may be seen in young stock.