The surface ultrastructure of the Egyptian liver fluke Fasciola gigantica.

Scanning electron microscopy (SEM) of adult Fasciola gigantica, a known liver fluke in Egypt, shows the presence of tegumental spines and folds giving the appearance of a rough surface. The spines are small and closely-spaced anteriorly, increasing in size and number on the in the mid-lateral aspect of the ventral surface. Towards the posterior end the spines progressively decrease in both size and number. Tegumental transverse folds or invaginations are interspaced between the spines. There are two types of sensory papillae on the tegumental surface. The dorsal surface exhibits similar features but the spines and papillae are less numerous with less extensive surface folds than on the ventral surface of the body. The oral and ventral suckers, together with the excretory pore, appear spineless, bearing ciliate sensory papillae. Further studies should be directed at deciphering the genetic codes and the synthesis of some of these antigens by recombinant DNA technology to be used in serodiagnosis, vaccination and for drug receptors.