Phylum Nematoda

The "Roundworms"

Everywhere in the soil, genetically historic, and the cause of some really funky diseases…

  1. Unifying Characteristics
    1. Aquatic, terrestrial, and parasitic species
    2. Triploblastic, Psuedocoelomate, non-segmented
    3. Covered with cuticle, no external cilia.
    4. Epidermis expands into body cavity.
    5. Muscle fibers arranged only longitudinally.
    6. Excretory system of gland cells and/or canals.
    7. Male duct opens into rectum, female has gonopore, has anus.
    8. Examples:

Name of Disease

Causative Organism


Definitive test

Human Ascaroid

Ascaris lumbricoides

Drinking infected (sewage) water

Stool sample


Necator americanus

Walk barefoot on soil w/ juvenile

Fecal Sample


look for eggs


Trichinella spiralis

Eating pig meat w/encysted

T. Spiralis

Tissue Sample of Muscles look for encysted T. Spiralis


Wucheria bancrofti

Mosquito Bite

Blood Sample look for microfilaria

Guinea Worm

Dracunculus medianansis

drink water/ swallow cyclops

blood test, look for microfilaria

River Blindness

Oncocerca volulus

Black Flies


Eye Worm

Loa loa

Deer fly


Dog Heartworm

Dirofilaria immitus

Mosquito, mostly Aedes culex