ABSTRACT
Flukes (trematodes) are a large group of ›attened, rhomboidal-shaped worms that parasitize various mollusks and vertebrates. Taxonomically, ›ukes are classi‘ed in the class Trematoda covering 18,000-24,000 species, which is further divided into two subclasses: the Aspidogastrea (comprising about 100 species of obligate parasites of mollusks as well as turtles and ‘sh) and the Digenea (comprising the remaining species of obligate parasites of both mollusks and vertebrates, but rarely cartilaginous ‘sh). The main biological difference between the subclass Aspidogastrea and the subclass Digenea is that Aspidogastrea larvae do not multiply, while Digenea larvae do.
