Intracellular Campylobacter-like Organisms Associated with Rectal Prolapse and Proliferative Enteroproctitis in Emus (Dromaius novaehollandiae)

Abstract

Rectal prolapse was the presenting clinical finding in a group of juvenile emus ( Dromaius novaehollandiae). Gross findings included severely thickened and rugose distal rectal mucosae. Histologically, there were thickened villi, enterocyte hyperplasia, dilated glands filled with mucus and heterophils, and a dense infiltrate of heterophils, macrophages, lymphocytes, and plasma cells in the lamina propria. Examination of Warthin-Starry silver-stained sections revealed numerous apically located comma-shaped intracytoplasmic bacteria approximately 1X3 μm in size. Campylobacter-like organisms morphologically compatible with ileal symbiont intracellularis now known as Lawsonia intracellularis were seen via electron microscopy. Bacteria were further characterized by indirect immunofluorescence using a monoclonal antibody specific for the 25-27-kd outer membrane protein of L. intracellularis.