INTRODUCTION TOTISSUE NEMATODES & FILARIAL WORMS

By: Ferle C. Estera/Velez college student/afraid of cockroaches

TISSUE NEMATODESHow are intestinal nematodes differ from tissue nematodes?

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

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

SUPERFAMILY: THELAZIOIDAEThelazioidea 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

SUPERFAMILY: FILARIOIDEA Family: Acanthocheilonematidae

FILARIAL WORMSWhat are the common filarial spp. in man?

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.

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

Click icon to add pictureSheathed

Unsheathed

• Burgia malayi,• Wuchereria

bancrofti • Loa loa

• M. Perstans• M. Ozzardi• M. Streptocerca• O. volvulus

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

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

Parasites Adult Microfilaria

Periodicity Vector

LYMPHATIC

W. bancrofti Lymphatic blood Nocturnal culex, aedes, anophelesB. malayi Lymphatic blood Nocturnal Aedes, anoph, mansoniB. timori Lymphatic blood Nocturnal AnophelesSUBCUTANEOUS

L. loa Connective blood Diurnal chrysopsO. volvulus Connective skin Non periodic SimuliumM. streptocerca Dermis skin Non periodic CulicoidesSEROUS CAVITYM. perstans Body cavity blood Non periodic Culicoides

M. ozzardi Body cavity blood Non periodic Culicoides

Locat ion in body

METHODS OF IDENTIFICATIONBlood concentration technique

Knott’s concentration technique: 2% formaldehyde, centrifuge, methanol, giemsa smear

Membrane filtration: Nucleopore, Syringe

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

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

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:

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:

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

MAJOR FILARIAL INFECTIONS OF HUMANSLab. 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

END