1. TISSUE NEMATODES
TISSUE NEMATODES

2. Common Tissue Nematodes
Trichinella spiralis adults in small intestine larvae in tissues (mainly in muscles).
Toxocara canis (dog roundworm) larvae in organs (liver brain eyes), causing visceral larva migrans
Dracunculus medinensis (guinea worm) adult female in subcutaneous tissues
Filarial worms

3. Life-cycle of Trichinella spiralis

4. Trichinosis: geographic distribution

5. Most prevalent in areas where domestic pigs are allowed to roam freely.

6. Trichinosis Pathology: Adults cause mild gastroenteritis.
Larvae cause fever, myositis and multi-system involvement which may lead to death.
Diagnosis: serology, muscle biopsy.
Treatment: Albendazole or Mebendazole + corticosteroids

7. Trichinosis

8. Visceral larva migrans:
Mainly affects children who eat soil contaminated with emberyonated (infective) eggs of Toxocara canis.
Larvae do not develop in humans but migrate continuously in viscera and encapsulate, causing tissue damage.

9. Toxocara canis

10. Toxocariasis Pathology: Eosinophilia, hepatomegaly, retinitis.
Diagnosis: serology, biopsy.
Treatment: Albendazole

11. Dracunculus medinensis

12. Caused by Dracunculus medinensis
Draunculiasis
Caused by Dracunculus medinensis
Adult female lives in subcutaneous tissues, causing a skin ulcer through which it protrudes its anterior end.
Main pathology due to secondary bacterial infection and allergic reactions.
Diagnosis: clinical picture.
Treatment: surgical removal.

13. FILARIAL WORMS: (Adult worms + microfilariae)
1 Wuchereria bancrofti, Brugia malayi & B. timori:
Lymphatic filariasis (adults in lymphatics,
microfilariae in blood)
2 Loa loa:
Adults in subcutaneous and subconjunctival tissues, causing Calabar swellings. Microfilariae in blood
3 Onchocerca volvulus:
Adults in subcutaneous swellings Microfilariae : mainly in skin, eyes causing River blindness

14. LYMPHATIC FILARIASIS

15. Lymphatic Filariasis

16. Life-cycle of Wuchereria bancrofi

17. LYMPHATIC FILARIASIS Mainly caused by Wuchereria bancrofti Pathology:
and Brugia malayi
Pathology:
Due to adult worm obstructing lymphatics.
Acute: lymphadenitis lymphatic varices
Chronic: lymphedema, hydrocele, chyluria.

18. LYMPHATIC FILARIASIS
Diagnosis: detection of microfilariae in blood in early stages of the disease:
Blood film, Knott’s method
( concentration of 1 ml of blood), best 10 PM to 2 AM (nocturnal periodicity).
Immunological tests
Treatment: diethylcarbamazine (DEC) or ivermectin

20. Loiasis

22. Loiasis
Pathology: Adult worm continously migration in subcutaneous and subconjuntival tissues, causing Calabar swellings (allergic reactions) and conjunctivitis.

23. Loiasis Diagnosis: detection of microfilariae in blood film.
Treatment: diethylcarbamazine (DEC) or ivermectin, surgical remonval.

24. Onchocerciasis

25. Onchocerciasis (river blindness)
Pathology:
Adults worms live in subcutaneous nodules.
Main pathology caused by microfilariae in:
Skin: dermatitis
Lymph nodes: lymphadenopathy
Eyes: blindness
Diagnosis: skin snip to identify microfilariae.
Treatment: Ivermectin

26. Onchocerciasis

27. Onchocerciasis

31. NON-FILARIAL TISSUE NEMATODE INFECTIONS
treatment
Diagnosis
Location in human
Mode of transmission
Disease
Nematode species
Surgical extraction
clinical
Subcutaneous, mainly in lower limbs
Ingestion of infected cyclops in water
Dracunculiasis, Guinea worm disease
Dracunculus medinensis
albendazole
Serology, muscle biopsy
Muscles, lungs brain
ingestion larvae in under-cooked pork
Trichinellosis (trichinosis)
Trichinella spiralis
Serology, ELISA
Abdominal organs and brain
Ingestion of infective eggs in soil
Visceral larva migrans
Toxocara canis

32. MAJOR FILARIAL INFECTIONS OF HUMANS
Lab. diagnosis
vector
Location of microfilaria
Location of adult in humans
Geographic distribution
Disease
species
Blood film
mosquitoes
Blood (nocturnal periodicity)
Lymphatic vessels
Tropical and subtropical areas
elephantiasis
Wuchereria bancrofti
Asia
Brugia malayi
Skin snip
Simulium spp. (black fly)
Skin, eyes, no periodicity
Subcutaneous nodules
Africa, Central and South America, Yemen
Onchocerciasis (river blindness)
Onchocerca volvulus
Chrysops spp. (deer fly)
Blood (diurnal periodicity)
Moving in subcutaneous tissues
Central Africa
loiasis
Loa loa