OBSERVATION ON EXSHEATHMENT OF GNATHOSTOMA SPINIGERUM LARVA AND ITS PENETRATION THROUGH THE STOMACH WALL OF CYCLOPS

The mechanisms of Gnathostoma spinigerum larval exsheathment have been investigated. In our finding, after exposure to several proteases and chemicals, the sheath was shown as non-cuticle in nature and did not contain chitin by the use of Calcofluor dye. It appeared to be the first time that the process of penetration was live demonstrated, captured and followed in a single cyclops. It was found that the minimum time required for penetration into the body cavity through the stomach wall of the cyclops after ingestion of sheathed larvae was as early as 10 min. However it is still unclear whether, the mechanisms of exsheathment and penetration are enzymatic, mechanical or combined. Chiang Mai MedBull 2005;44(2):79-83.