1. The Ecdysozoa
The Ecdysozoa include the following phyla: Arthropoda, Onychophora, Tardigrada, Kinorhyncha, Priapulida, Loricifera, Nematoda and Nematomorpha.

2. The Ecdysozoa Characteristic shared by ecdysozoans
Three-layered cuticle composed of organic material, which is periodically molted as the animal grows.
The process of molting is called ecdysis and gives the group its name.
The Ecdysozoans lack locomotory cilia, produce mostly amoeboid sperm.
Their embryos do not undergo spiral cleavage as in most other protostomes.

3. Phylum Nematoda
the roundworms

4. Phylum Nematoda
Nematodes are among the most abundant animals on earth - over 25,000 species have been described.
Majority of nematodes are free-living in every conceivable habitat.
free-living species are commonly microscopic in size.
A few species cause disease of great importance to humans and domestic and wild plants and animals.

5. Phylum Nematoda
If all the matter in the universe except the nematodes were swept away,…we should find our world’s mountains, hills, vales, rivers, lakes and oceans represented by a thin film of nematodes.
N.A. Cobb (1914, Yearbook of the United States Department of Agriculture) 5

8. Phylum Nematoda Parasitic and free-living Numerous and diverse
6.7 ml of coastal mud
1,074 individuals
236 species
Rotting apple:
90 thousand individuals
Farmland:
9 billion per acre 8

9. Phylum Nematoda Roundworms Dioecious (mostly) Tapered at both ends
Pseudocoelomate
Pseudocoel
Complete digestive system
Mouth and anus 9

10. Pseudocoelomate Characteristics
“false” body cavity
ectoderm
pseudocoelom
mesoderm
Gut
endoderm
the pseudocoelom is lined by mesoderm
on ONE side only 10

11. Characteristics of the Phylum Nematoda11

12. Phylum Nematoda Triradiate pharynx Pharynx between mouth and esophagus12

13. Photo by Agustín Jimenez13

14. 14

15. Phylum Nematoda Body covered by: Cuticle Noncellular Molts
4 times during development 15

16. Elaboration of Cuticle
Aspidodera 16

17. Phylum Nematoda Movement Contraction of muscles
Longitudinal muscles
Hydrostatic skeleton
Fluid filled pseudocoel
Cuticle
Contraction of muscles
Antagonized by pressure of pseudocoel and hydrostatic skeleton 17

18. Tube within a tube
Female
Esophagus
Uterus
Vulva 18

19. Tube within a tube
Male
Cloaca = common area for openings of genital pore and anus 19

20. Copulatory Spicules Hold vulva open during copulation20

21. Reproduction Dioecious Some Monoecious (rare) Parthenogenesis
Females reproduce without males
Unfertilized eggs develop into new individuals
Sometimes systems are mixed (heterogamy)
Mate Finding
Pheromones
Thigmotaxis (papillae near reproductive structures) 21

22. Mating Behavior Male coils tail around female and searches for vulva.22

23. Papillae
Sensory structures 23

24. Characteristics of the Phylum Nematoda
Nematode development is similar in all nematodes.
 Consists of 4 juvenile stages between the egg and adult. Each stage is separated by a molt of the cuticle.
Hatch M M M M4
Egg J J J J Adult
Juvenile stages may be passed within the egg, free-living in soil, parasitic in an intermediate host, or parasitic in definitive host. 24

25. parasite of soybean plants parasite of tomato plants
Ecology
Many nematodes are important parasites of both plants and animals.
parasite of soybean plants
parasite of tomato plants

26. Parasitic Nematodes 26

27. Order Oxyurida
Rhoden and Bolek (2011)

28. Order Oxyurida
Rhoden and Bolek (2011)

29. Order Oxyurida Enterobius vermicularis Large esophageal bulb
Pinworms
Enterobiasis
Large esophageal bulb
Sharp, pointed tail
Alae at anterior end
Cosmopolitan
Common in people
Relatively unpathological

30. Direct life cycle
Adults live in ileocecal region of intestine (wander throughout gut)
Feed on bacteria and organic material from cells
At night, females migrate to anus and lay eggs (up to 16,000 each)
Embryonates within 6 hours
Infection via ingestion of embryonated eggs
Or may hatch on perianal folds and wander up intestine

31. Symptoms and Pathology
1/3 asymptomatic
Pruritus
Lesions from feeding not significant
Secondary infections can occur
Itching can lead to secondary infections

32. Pinworm Neurosis Nervousness Children Parents
Fidgeting, restlessness, irritable, nail biting, nose picking
Due to toxemia and damage of epithelium
Children
Parents
Obsessive cleaning

33. Diagnosis Scotch tape test Flashlight test Mebendazole
Treat entire family

34. Diagnosis of Enterobius vermicularis
Use of double-stick tape on a tongue depresser.
This is pressed against the perianal folds where eggs will stick to the tape.
Tape is then stuck onto a microscope slide and examined for eggs.

35. Enterobius vermicularis
Almost anybody can become infected with this parasite. No social class is exempt. These parasites soon become "family affairs".
Once one person, usually a child becomes infected, other family members will undoubtedly also become infected.

36. Epidemiology Very Prolific Eggs build up fast
Clothing and bedding
Eggs very light and float
Easily distributed
Eggs viable for up to a week

37. Prevention and Control
Not very serious
Good hygiene

38. Horse Pinworms, Oxyuris equi

39. Horse Pinworms, Oxyuris equi

40. Horse Pinworms, Oxyuris equi

41. Guinea worm (Dracunculus medinensis):

42. Guinea worm (Dracunculus medinensis):
Transmitted by infected copepods in drinking water
Juveniles move into the body cavity
Female adult migrates to the subcutaneous tissue, causes an ulcer/blister, and releases juveniles through hole when host comes in contact with water

43. Guinea worm (Dracunculus medinensis):
Traditionally removed by winding the worm around a stick over the course of several days
This may be the basis for the Caduceus symbol used in the medical field

44. Juvenile Dracunculus medinensis and Copepod Intermediate host

45. Life Cycle

47. Drinking Water
Guinea worm sufferers often try to ease the burning pain caused by the blister by stepping into water—the very same source of drinking water for their community.

48. Guinea worm (Dracunculus medinensis):
Female worms cause allergic reactions during blister formation, causing an intense burning pain producing allergic reactions (rashes, nausea, diarrhea, dizziness, and localized edema).
When the blister bursts, allergic reactions subside, but skin ulcers form, through which the worm can protrude.
Only when the worm is removed is healing complete. Death of adult worms in joints can lead to arthritis and paralysis in the spinal cord.

49. Carter Center: Guinea Worm Eradication
Jimmy Carter
39th President of the United States

50. Distribution

51. Controlled Immersion

52. Current Distribution

53. Chad, Ethiopia, Mali, and South Sudan