Periodic acid-schiff (PAS) staining best highlights the intrabronchial mucus plugs in their characteristic forms known as
Curschmann spirals, which can occlude the airspaces totally and are heterogenous mixtures of mucins, plasma exudates, and inflammatory cells that are primarily eosinophils.
During the examination of a respiratory specimen for cellular constituents, virologists may encounter unfamiliar cells, cell fragments,
Curschmann spirals, and artifacts, some of which simulate microorganisms.