Helminths

Helminths are multicellular eukaryotic animals. Many are parasitic. Helminths can be dioecious (male and female individuals) while some are hermaphroditic (having male and female reproductive organs). The definitive adult harbors the sexually mature adult helminth while intermediate hosts may be necessary for developmental stages. Platyhelminths or flatworms are flattened from front to back. The digestive system is incomplete as there is an opening for food to enter and an opening for waste to exit. Trematodes or flukes have flat leaf shaped bodies with a ventral sucker and an oral sucker to hold them in place and suck fluids from the host. They also obtain food by absorption through their cuticle. Cestodes or tapeworms are intestinal parasites. The nematodes or roundworms are cylindrical and tapered at the ends. They have a complete digestive system and many human parasites are found in this group. LOMO, Konus, and Greiner Bio-One make products used in parasite research.