Granulomatous enteritis and lymphadenitis in Iberian pigs naturally infected with Lawsonia intracellularis

Intestinal samples and/or lymph nodes of two Iberian pigs from two differen t farms were submitted for histopathologic examination. Both pigs had proli feration of ileal and/or cecal crypts with almost complete absence of goble t cells. Infection by Lawsonia intracellularis was demonstrated by immunohi stochemistry and polymerase chain reaction assay. The mesenteric lymph node of one pig had moderate lymphocyte depletion with granulomatous inflammati on of the lymph node parenchyma. Histiocytes and multinucleated giant cells from the lymph node of one pig contained L. intracellularis antigen within the cytoplasm. This pig had also porcine circovirus type 2 (PCV-2) infecti on, but nucleic acid and antigen of this virus were not demonstrated in the lymph node. The second pig had lymphocyte depletion and marked granulomato us inflammation in Peyer's patches. Histiocytes and multinucleated giant ce lls in areas of granulomatous inflammation contained L. intracellularis ant igen; no PCV-2 nucleic acid or antigen was detected in the tissues of this pig. This is the first description of granulomatous ileitis and lymphadenit is associated with L. intracellularis infection.