The
ultrastructure of experimentally recovered Fasciola
gigantica shows that vitelline cells are grouped in vitelline follicles.
Vitelline cells developed through a series of developmental stages. At stage I
of vitelline cell development, the nucleo-cytoplasmic ratio is high and the
cytoplasm has many elongated mitochondria. In
the stage II, the cisternae of endoplasmic reticulum is appeared, the formation
of shell protein globules is started and the cell increases in size, while the
nucleo-cytoplasmic ratio decreases. At the final stage of development, stage
III, the prominent structure is the domination of shell protein globules as the
vitelline cell is fully matured and ready to deliver its shell protein globules
to the fertilized eggs. This study is the first to show the fine structure of
vitelline cells of F. gigantica
recovered from experimentally infected mice. The present work opens the way for
more studies on experimentally recovered digenean worms and also exploring
strategies for fighting the diseases caused by these worms.