Introduction to Tissue Nematodes and Filarial Worms

Parasitology - Introduction to Tissue Nematodes and Filarial Worms

1. Introduction to Tissue Nematodes & filarial worms By: Ferle C. Estera /Velez college student/afraid of cockroaches

2. Tissue Nematodes How are intestinal nematodes differ from tissue nematodes?

3. Subclass: Spiruria Suborder : Spirurida Suborder : Camallanina Species : Dracunculus medinensis Superfamily: Filarioidea Thelazioidea Species : Onchocerca volvulus   , Loa loa , Mansonella   , Dirofilaria repens , Wuchereria bancrofti , Brugia malayi , Brugia timori   Species: Gnathostoma spinigerum

4. Suborder: camallanina The  Camallanina  are a suborder  of  nematodes . Species: Dracunculus medenensis (human as final host) Parasites  of terrestrial and  aquatic vertebrates Copepods  as obligatory  secondary hosts

5. Superfamily: Thelazioidae Thelazioidea  is a  superfamily  of  spirurian   nematodes  in the large  order   Spirurida . Like all nematodes, they have neither a  circulatory  nor a respiratory system . Species: Gnathostoma spinegerum

6. Superfamily: Filarioidea Family: Acanthocheilonematidae

7. Filarial worms What are the common filarial spp. i n man?

8. Filarial Worms Generalities Live in tissues or body cavities of a vertebrate host Slender, threadlike worm usually 2 to 1 cm Common habitat : circulatory system, lymphatic system, connective tissue and serous cavities These are transmitted by blood sucking insects Requires two hosts to complete the cycle.

9. Morphology Produces less differentiated microfilariae Microfilariae - are highly motile, threadlike pre larva that in some species may retain egg membrane as SHEATH or it raptures to become naked or UNSHEATHED Microfilaria are capable of living a long time in the vertebrate host, but cannot develop further until ingested by an intermediate host. Microfilariae transforms into infective larvae in the insect and are deposited in the next host when insect takes its blood meal Female worms are viviparous Males are smaller than females

10. Sheathed Unsheathed Burgia malayi , Wuchereria bancrofti Loa loa M . Perstans M . Ozzardi M . Streptocerca O. volvulus

11. General Life cycle Infective third stage larvae are transmitted to man by infected biting arthropods during a blood meal Inside the arthropod, the microfilariae develop in 1 to 2 weeks into infective filariform ( third stage larvae ) The adults dwell in various human tissues where they can live for several years Larva migration and development takes place in the tissue Definitive host : man

12. Periodicity Nocturnal - largest no. of microfilariae found in peripheral blood is at night Diural - Largest no. of microfilariae found in peripheral blood during day Non periodic- largest no. of microfilariae circulating at some what constant levels during day and night Sub periodic- Microfilariae detected throughout the day but are detected in a larger number during late afternoon

13. Parasites Adult Microfilaria Periodicity Vector LYMPHATIC W. bancrofti Lymphatic blood Nocturnal culex , aedes , anopheles B. malayi Lymphatic blood Nocturnal Aedes , anoph , mansoni B. timori Lymphatic blood Nocturnal Anopheles SUBCUTANEOUS L. loa Connective blood Diurnal chrysops O. volvulus Connective skin Non periodic Simulium M. streptocerca Dermis skin Non periodic Culicoides SEROUS CAVITY M. perstans Body cavity blood Non periodic Culicoides M. ozzardi Body cavity blood Non periodic Culicoides Location in body

14. Methods of Identification Blood concentration technique Knott’s concentration technique : 2% formaldehyde, centrifuge, methanol, giemsa smear Membrane filtration : Nucleopore , Syringe

15. Pathology Clinical manifestations mainly by the adult worms Immunologic responses, both humoral and cell-mediated Dead or dying worms elicit the most severe inflammation Calcification of necrotizing granulomas with dead worms lead to lymphatic obstruction

16. Manifestation Acute filarial disease “acute attacks” Episodes of febrile lymphangitis and lymphadentis Adenolymphangitis (ADL) dermatoadenolyphangitis (DADL) Pain, tenderness and swelling of affected areas (limbs, genitals, breast) w/ or w/out fever Epididymo-orchitis in males may occur

17. Lymphedema - An abnormal accumulation of lymph in tissues causing swelling of legs , arms, breasts, or genitals Elephantiasis - disabling and disfiguring lymphedema of the limbs, breast and genitals , accompanied by marked thickening of the skin Presence of parasite in lymphatic system can lead to:

18. Hydrocele - Fluid-filled ballon -like enlargement of the sacs around the testes Kidney damage- leading to blood and protein loss in urine Presence of parasite in lymphatic system can lead to:

19. 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 NON-FILARIAL TISSUE NEMATODE INFECTIONS

20. 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 Blood film mosquitoes Blood (nocturnal periodicity) Lymphatic vessels Asia elephantiasis 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 Blood film Chrysops spp. (deer fly) Blood (diurnal periodicity) Moving in subcutaneous tissues Central Africa loiasis Loa loa

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