2 Class Trematoda 3 Class Monogenea o Both

2. Class Trematoda & 3. Class Monogenea: o Both are parasitic flukes n Leaf-shaped flatworms o Endoparasites: n Live in blood, intestines, lungs, liver, etc. o Ectoparasites: n Live on external surfaces of aquatic hosts

Structure of Flukes o Anterior & ventral suckers for attachment to host o Nervous system like planarian n Except NO eyespots o Tegument – outer layer that protects from host’s immune and digestive system

Liver fluke

Reproduction of flukes: n Most are hermaphroditic n May release 10, 000+ eggs at a time! n Complicated life cycle (p. 692)

Life Cycle: o Primary host: adult parasite gets nourishment from this host n Sexual reproduction o Intermediate host: larvae derive nourishment here n Asexual reproduction

Fluke Diseases in Humans o Swimmer’s itch: minor skin irritation and swelling n Small brown fluke in lakes (in Ohio) n Dies within skin because humans are not ideal hosts

Video 1 Video 2 o Schistomiasis (blood fluke): disease that causes tissue damage, bleeding, tissue decay and possible death n Lungs, intestine, bladder, & liver n 200 million people affected worldwide

Schistosoma Animation! Secondary or Intermediate host • snail Primary host • human

Swimmer’s itch

4. Class Cestoda o 5, 000 species of tapeworms o Can live in intestines of most vertebrates o Enter through undercooked food with eggs or larvae (cyst) o Symptoms of infection: n n Digestive problems Weight loss Lack of energy anemia

Structure: o Tegument to protect from host n Also absorbs nutrients from host o Scolex: knob-shaped organ with hooks and suckers to attach to host o Proglottids: body sections after a short neck n Up to 2, 000 per tapeworm!

Reproduction: o Hermaphrodites o Each proglottid has ovaries and testes n Filled with 100, 000+ eggs each! n Eggs fertilized by sperm of different proglottid

Life Cycle: o Cysts: dormant larvae surrounded by protective covering in animal muscle