RESUMEN
Cestoda is a class of parasitic worms in the flatworm phylum (Platyhelminthes). Most of the species-and the best-known-are those in the subclass Eucestoda; they are ribbon-like worms as adults, known as tapeworms. The results reported that about 9.94% of selected sheep were infected with tape worms in native breed. Concerning the seasonal incidence of tape worms among sheep, the results revealed that the highest percentage was recorded during winter season (11.3%), while the lowest percentage was recorded during the spring (7.72%). The species of tape worms recorded were Moniezea expansa, Moniezea benedene, Avitellina centripunctata, Thysaniezia giardia and Stilesia hepatic. Molecular characterization of Al Taif Moniezia species cox1 gene records four different species Me Taif1, Me Taif2, Me Taif3 and Me Taif4, that have identity ranged from 90 to 99% to species in Senegal and Ethiopia (Me13, Me14 and Me22). In vitro treatment of Monizia spp. with different concentrations (10, 20, 30 and 50 µglml) of Spirulina platensis extract (Blue-green Algae) affects the morphological architecture of tape worms by using scanning electron microscopy (SEM). The results revealed that Spirulina platensis extract treatment, especially for higher doses 30 and 50 µglml, caused the sucker opening to narrow as a result of scolex swelling more than usual, deformation of the proglottids occurred with circular areas of declare swelling along their margins and microtriches covering the whole tegument appears in several directions. In conclusion, as per of our knowledge it is the first time to record new species of Moniezia species in Al Taif governorate and the anthelmintic potential of Spirulina platensis.