Fig. 1.

Hematoxylin–eosin (HE) staining and chromogenic in situ hybridization (ISH) of the colon of a quail. (A) In the HE staining large amounts of parasite-like objects are visible in the gut lumen. Bar = 100 μm. Inset: trichomonads are oval to pear-shaped with a discernible axostyle and parabasal body. Bar = 30 μm. (B) In the ISH using the OT probe distinct black signals corresponding to the parasite-like objects can be seen in the intestinal lumen, crypts and lamina propria mucosae. Bar = 100 μm.