Left panel: A cluster of ciliated columnar epithelial cells. Right panel: In horses, macrophages can be binucleated (arrow) or multinucleated (short arrow). There is a pigmented (dematiaceous) fungal hyphus (e.g. Alternaria species) attached to the macrophage (arrowhead). These environmental inhabitants are frequently inhaled and can contribute to symptoms of asthma in some horses. Modified Wright’s stain.
