1. Class Nematoda

2. General characters Cylindrical round worms with tapering ends
Separate sex, the female is usually larger than the male
No intermediate host
Infective stage: embryonated egg
Body is usually tapered to a pointed posterior end, and to a rounded anterior end
They are classified into 2 main categories according to their primary location in the body:
Intestinal nematodes
Tissue nematodes (filariae)

3. Examples of Class Nematoda
Intestinal nematodes:
Trichuris trichiura
Ascaris lumbricoides
Enterobius vermicularis
Anclystoma duodenale
Trichinella spiralis
Tissue nematodes: Lymphatic filariae
Wuchereria bancrofti

4. Trichuris trichiura (whip worm)
Egg: barrel shaped with 2 transparent mucoid plugs (H.P)
Adult male 4 cm long. Posterior end is curved and provided with 1 spicule (magnifier)
Adult female 5 cm long, larger than male. Posterior end is straight and blunt . (magnifier)

5. Trichuris trichiura
Location of adult: large intestine of man
Infective stage : embryonated egg
Mode of transmission: ingestion of food contaminated with embryonated eggs
Diagnosis: eggs in stool
Disease: Trichuriasis

6. Ascaris lumbricoides
Anterior ends (ascaris lips): mouth surrounded with 3 lips and provided by sensory papillae (Magnifier)
Egg :rounded with coarsly mamillated wall
Posterior end of male: curved with 2 spicules (Magnifier)

7. Ascaris lumbricoides Location of adult: Small intestine of man
Infective stage: embryonated egg
Mode of transmission: ingestion of food (green vegetables) contaminated with embryonated egg
Diagnosis: eggs in stool
Disease: Ascariasis

8. Enterobius vermicularis (pin worm, oxyuris)
Female (10mm) Posterior end is straight with,long pointed tail
Egg: Planoconvex or D shaped egg
Male (5mm): Posterior end is curved with one spicule

9. Enterobius vermicularis (pin worm, oxyuris)
Location: large intestine of man
Infective stage: embryonated egg
Mode of transmission: ingestion of food contaminated with embryonated egg or autoinfection via nails scratching the perianal region
Diagnosis: eggs in anal or perianal swab collected using transparent adhesive tape. rarely in stool
Disease: Enterobiasis

10. Hook worms: Anclystoma duodenale
Posterior end of male ending with copulatory bursa which is supported with rays
Anterior end showing buccal capsule having 2 pairs of teeth, 2 dental plates

11. Anclystoma duodenale Location of adult: small intestine of man
Infective stage: filariform larvae
Mode of transmission: penetration of filariform larvae in skin through bare feet
Diagnosis: eggs in stool
Disease: Hook worm infection

12. Trichinella spiralis
Female: 3 mm long, posterior end blunt, vulva (genital organ) opens at the junction of the anterior fifth with the rest of the body
Encysted larva in muscle

13. Trichinella spiralis Location of adult: small intestine of man
Location of larvae: encysted in striated muscles
Infective stage: encysted larvae in striated muscle
Mode of transmission: ingestion of undercooked pork containing encysted larvae
Diagnosis: muscle biopsy to identify larvae in striated muscles
Disease: Trichinosis

14. Wuchereria bancrofti
Microfilaria: sheathed body, curved, tapering tail, nuclear column are visualized individually and do not extend to the tip of tail

15. Wuchereria bancrofti Location of adult: lymphatics and lymph nodes
Infective stage: infective filariform larvae in the mouth parts of mosquito
Vector (intermediate host):
mosquito ( Anopheles or Culex sp).
Mode of transmission: bite of mosquito having infective filariform larvae
Diagnosis: Microfilaria in blood film
Disease: lymphatic filariasis