Contrast staining of Trichinella spiralis larvae in fresh, frozen and formalin preserved muscles.

Fresh, frozen-thawed and formalin-preserved muscle samples heavily infected with Trichinella larvae were cut into several pieces and stained with Giemsa and Leishman and the reference Haematoxylineosin (H & E) stain. Observation under microscope revealed that both muscle larvae and nurse cells in fresh and formalin preserved specimens appeared as purplish blue structures contrasting with the pinkish color of non-infected muscle fibers in both Giemsa and Leishman stains. These findings were confirmed in H & E stained samples. However, frozen samples did not show contrast stain.