Development and hatching mechanism of Fasciola eggs, light and scanning electron microscopic studies

摘要

Both light microscopy and scanning electron microscopy were used in the description. There were variable measurements of eggs from the same fluke and there was no relationship between the size of the fluke and size of eggs. Light microscopy revealed that the operculum has different shapes in Fasciola gigantica and F. hepatica. Under normal laboratory conditions of temperature (26+/-1^oC), miracidia of F. gigantica developed within 12-16days period, but those of F. hepatica developed within a period of 13-15days. The miracidia of F. gigantica measured 110x70@mm and that of F. hepatica measured 136x74@mm. The life span of the miracidium in F. gigantica ranged between 9 and 12h, while in F. hepatica the life span did not exceed 10h. Miracidial epidermal plates in miracidium of F. gigantica were found to be 20 plates arranged in four tiers of six, four, six and four. Hatching process was recorded using scanning electron microscope, and it indicated partially opened operculum.