Introduction to Tissue Nematodes and Filarial Worms
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Intestinal nematodes live in the intestines of their hosts, while tissue nematodes live in other tissues like lymphatic vessels, skin, and eyes. Some common filarial nematode species that infect humans are Wuchereria bancrofti, Brugia malayi, Onchocerca volvulus, and Loa loa. They are transmitted by blood-sucking insects and have complex life cycles involving microfilariae that develop into infective larvae in insects before infecting humans. Adult worms live in lymphatic vessels, skin, or subcutaneous tissues and can cause diseases like elephantiasis or onchocerciasis.
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Introduction to Tissue Nematodes and Filarial Worms
- 1. By: Ferle C. Estera/Velez college student/afraid of cockroaches
- 2. How are intestinal nematodes differ from tissue nematodes?
- 3. • 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. 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. 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
- 7. What are the common filarial spp. in man?
- 8. 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. 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
- 12. 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
- 13. 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
- 14. 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 L o c a t i o n i n b o d y
- 15. Blood concentration technique Knott’s concentration technique: 2% formaldehyde, centrifuge, methanol, giemsa smear Membrane filtration: Nucleopore, Syringe
- 18. 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
- 19. 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
- 20. 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:
- 21. 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:
- 22. treatmentDiagnosisLocation in human Mode of transmission DiseaseNematode species Surgical extraction clinicalSubcutaneous, mainly in lower limbs Ingestion of infected cyclops in water Dracunculias is, Guinea worm disease Dracunculus medinensis NON-FILARIAL TISSUE NEMATODE INFECTIONS
- 23. MAJOR FILARIAL INFECTIONS OF HUMANS Lab. diagnosis vectorLocation of microfilaria Location of adult in humans Geographic distribution Diseasespecies Blood filmmosquitoesBlood (nocturnal periodicity) Lymphatic vessels Tropical and subtropical areas elephantiasisWuchereria bancrofti Blood filmmosquitoesBlood (nocturnal periodicity) Lymphatic vessels AsiaelephantiasisBrugia malayi Skin snipSimulium spp. (black fly) Skin, eyes, no periodicity Subcutaneous nodules Africa, Central and South America, Yemen Onchocerciasi s (river blindness) Onchocerca volvulus Blood filmChrysops spp. (deer fly) Blood (diurnal periodicity) Moving in subcutaneous tissues Central Africa loiasisLoa loa