The document describes several nematode parasites including Trichuris trichiura, Trichinella spiralis, Capillaria, Ascaris lumbricoides, Enterobius vermicularis, Wuchereria bancrofti, and Ancylostoma caninum. For each nematode, key defining characteristics, pathogenesis, taxonomy, and life cycle stages are outlined. Morphological differences between nematode adults, eggs, and larvae are discussed. Functions of anatomical structures like phasmids, amphids, and muscles are also explained.

1. Presented by:
Group 3 (Fantastic
Amoeba)

2. Phylum Nematoda
(Greek: thread)
Defining Characteristics:
 Paired amphids ( anterior chemosensory organs)
 Vermiform with circular cross section(roundworms)
 No Circulatory System
 Excretory system: renette
 Linear Digestive System
 Syncytial
 Undergo ensheathment
 Undergo chromosome diminution

3. Trichuris trichiura
Defining Charactristics:
 “ Whip worm”
 Most common gastrointestinal parasites of human
 Lack lips
 Have stichosome esophagus
 Eggs possess plugs
 Male have coiled posterior end
Pathogenesis:
Trichuriasis
 Rectal prolapse
 IH: none

4. Trichuris trichiura
Taxonomic Key:
Phylum: Nematoda
Class: Aphamida
Order: Trichurida
Family: Trichuridae
Genus:Trichuris
Species: Trichuris trichiura

5. Trichuris trichiura Female
Mouth
Stichosome

6. Trichuris trichiura Male
Mouth
Stichosome
Testes
Copulatory spicule

7. Trichinella spiralis
Defining Characteristics:
 “ Trichina Worms”
 One of the smallest nematode
 Have calcified cystic wall
 Pathogenesis:
Trichinosis
IH and DH: the same
Diagnosis:
 Xenodiagnosis

8. Trichinella spiralis
Taxonomic Key:
Phylum: Nematoda
Class: Aphasmida
Order: Trichurida
Family: Trichinellidae
Genus: Trichinella
Species: Trichinella
spiralis

9. Trichinella spiralis Encysted
Larva

10. Capillaria
Defining Characteristics:
 Gradual caudal and cephalic transition
 Eggs have two plugs with pits
Pathogenesis:
Capillariasis
IH: fish
 Capillaria philippinensis

11. Capillaria
Taxonomic Key:
Phylum: Nematoda
Class: Aphasmida
Order: Trichurida
Family: Capillariidae
Genus: Capillaria
Species: Capillaria

13. Capillaria
plugs
 pits

14. Ascaris lumbricoides
Defining Characteristics:
 “Intestinal Roundworm”
 Chromosome diminution
 Have three lips
 Coelomocytes (cells found in pseudocoel)
Pathogenesis:
 Ascariasis
 Pneumonitis
 Transplacental migration

15. Ascaris lumbricoides
Taxonomis Key:
Phylum: Nematoda
Class: Phasmida
Order: Ascaridida
Family: Ascaridoidea
Genus: Ascaris
Species: Ascaris
lumbricoides

16. Ascaris
lumbricoides
Female c.s.
Cuticle
Hypodermis
Muscular layer
Ovaries
Intestine
Uterus
Pseudocoel

17. Ascaris
lumbricoides
Male c.s.
Cuticle
Hypodermis
Muscular layer
Testes
Intestine
Pseudocoel

18. Ascaris suum (Pig Ascaris)
Taxonomic Key:
Phylum: Nematoda
Class: Phasmida
Order: Ascaridida
Family: Ascaridoidea
Genus: Ascaris
Species: Ascaris
suum

19. Enterobius vermicularis
Defining Characteritics:
“Pinworms”
 Cuticle is transparent
 Have 3 small lips
 Male is minute
 Family affair
Pathogenesis:
 Itchiness and retrofection

20. Enterobius vermicularis
Taxonomic Key:
Phylum: Nematoda
Class: Phasmida
Order: Oxyurata
Family: Oxyuroidea
Genus: Enterobius
Species: Enterobius
vermicularis

21. Wuchereria bancrofti
Defining Characteristics:
 Invade lymphatic system and may cause
abstruction of lymph passages.
Pathogenesis
Elephantiasis or filariasis
IH: Anopheles mosquito

22. Wuchereria bancrofti
Taxonomic Key:
Phylum: Nematoda
Class: Phasmida
Order: Ascaridida
Family: Filarioidea
Genus: Wuchereria
Species: Wuchereria bancr

23. Wuchereria bancrofti

24. Ancylostoma caninum
Defining Characteristics:
 “Hookworm”
 Dentin in buccal capsule
 Male has copulatory bursa
Pathogenesis
Creeping eruption
Filariform: infective larva
Rhabditiform: juvenile stage

25. Ancylostoma caninum
Taxonomic Key:
Phylum: Nematoda
Class: Phasmida
Order: Stongylida
Family: Ancylostomatidae
Genus: Ancylostoma
Species: Ancylostoma
caninum

26. Ancylostoma caninum
Rhabditiform

27. Ancylostoma caninum
Filariform

28. Ancylostoma caninum
Female
Dentin/ teeth
Buccal capsule
Ovaries

29. Ancylostoma caninum Male
Dentin/ teeth
Buccal capsule
Copulatory bursa

30.  How do you differentiate morphologically
the adult forms and eggs of T. trichiura
and Capillaria?
 What is the characteristic of E.
vermicularis eggs making it easily
transmissible?
 How do you differentiate morphologically
the adult forms of Ascaris suum from A.
lumbricoides
 Differentiate: rhabditiform, filariform and
microfilaria

31.  Describe and give the function:
a. phasmids
b. amphids
c. renette
d. meromyarial muscles
e. polymyarial muscles
 Describe the molting pattern of
Nematodes. Which stage is usually
infective to the host?
 Why do eggs of Ascaris suum do not
readily infect humans and vice versa?