1. Phylum Nematoda

2. Basic Facts Name meaning: round worm Invertebrate Bilateral symmetry Body plan: Slender, unsegmented worms with tapering ends Digestive tract with 2 openings (food travels in one direction only!)

3. Basic Facts cont….. Exchange gases and excrete waste through skin Reproduction can be sexual or asexual Found in many habitats Most are free living, but some are parasites Muscular system present throughout body

4. Types of Roundworms Free-living: Found in all types of soil (Red worms) Present in vinegar (Vinegar eel)

5. Parasitic Roundworms Ascaris (Ascaris lumbricoides) Most common worm infection worldwide Eggs are passed through feces Humans/animals infected by eating food containing eggs (unwashed produce) Larva is circulated in blood stream, coughed up and swallowed into intestine

6. Filarial Worms Humans are infected through an intermediate host Medical condition: Elephantiasis Worms live in lymph nodes of host Infected by a mosquito containing eggs of worm Causes extreme swelling in host

7. Elephantiasis Pictures

8. Filarial Worms cont…. Medical Condition: Draculansis Caused by Guinea worm Host is infected by drinking contaminated water Intermediate host is a microscopic crustacean called a Cyclops

9. Guinea Worm cont…. Adult worm lives in the subcutaneous tissue of host Eggs are released through a wound in the host’s skin

11. Trichinella Medical condition: Trichinosis Larva forms cysts in muscle tissue Adult lives in the intestine Host is infected by eating contaminated meat that is undercooked or raw Can cause muscle damage and pain

12. Trichinella Pictures

14. Hookworm Scientific name: Ancylostoma sp. Host is infected by larvae in contaminated soil Larva burrows through skin to bloodstream Adult lives in the intestine

15. Hookworm Pictures

16. Pinworm Scientific Name: Enterobius vermicularis Host infected by swallowing eggs Adult lives in the lower digestive tract Eggs are laid in the perianal region of host Causes intestine itching and discomfort Very common in children Most common worm infection in the U.S.

17. Pinworm Photos