Wuchereria Bancrofti
It causes filariasis/ elephantiasis.
It is type of round worm, Wuchereria bancrofti or filarial worm causes elephantiasis or filariasis/ lymphatic.
Source and Mode of Transmission
Filariasis disease is transmitted by bite of infected female mosquitoes including;
1. Anopheles
2. Ades
3. Culex mosquito
Morphology
Adult worms are transparent, long -hair like structure, often creamy white in colour.
They are filiform in shape and both ends are tapering.
Size;
Male worm are 2.5-4.0 cm length and 0.1 mm thickness.
Female worm are 8-10cm length and 0.2-0.3 mm thickness.
Pathogenesis and clinical significance
Parasite enters in host body through bite of mosquito.
Infected filariform larva enters in various tissue of host and become adult.
The infection with this parasite is named wuchereriasis or filariasis. Disease is two types;
1. Classical filariasis (caused by adult worms)
2. Occult filariasis (caused by embryos)
1. Classical filariasis
Adult worms of parasite block lymphatic channels and cause classical filariasis in which enlargement of various body part occur, leads to lymphangitis, lymphoedema.
2. Occult filariasis
When parasite donot enter in blood only enlargement of lung, liver, spleen, lymph nodes called occult filariasis.
Adult worm may cause inflammation and irritation due to by action of toxins secreted by worms.
Symptoms
High fever
Chronic swelling genitalia, legs, arms, breast.
Skin exfoliation; removal of skin
Harden and thicken skin
Swollen lymph nodes (affect lymphatic system)
Life Cycle
Wuchereria Bancrofti passes its cycle in two host;
1. Man (definitive host)
2. Mosquito (Intermediate host)
When mosquito bites human being infective filariform larvae migrate by Saliva in host blood.
Larvae enter in various tissues of host and develop into adult male and female worms.
Adult worms block lymphatic channel and cause elephantiasis.
Adult worm live, in lymphatic system, male worm fertilize female worm.
Female worm releases infective microfilaria larvae in peripheral blood especially at night.
At night mosquito bites infective person and takes up microfilaria larvae with blood meal which multiply by binary fission in mosquito gut wall.
As result microfilaria converted into infective filariform larva which enter in salivary glands of mosquito, life cycle is repeated on mosquito bite.
1. Infective filariform larvae migrate by saliva, when mosquito bites human being.
2. In human body, larvae enter various tissue and reaches lymphatic channels.
3. Settle down in lymph nodes and develop into adult male and female worms.
4. Adult worm live in lymphatic channel and cause elephantiasis.
5. Male worm fertilize female worm and female worm releases infective microfilaria larvae in peripheral blood.
6. Microfilariae in men blood stream, mosquito during blood meal taken up microfilaria.
7. Microfilarial larvae multiply by binary fission into mosquito's gut wall.
8. Finally infective larvae enter in salivary gland of mosquito.
Laboratory Diagnosis
Specimen collection
Blood sample
Peripheral blood film examination
Important for observation of parasite in thick and thin smear with leishman's stain shows morphology of parasite.
Serological test
Include; IHA, ELISA, Immunofluorescence test
Treatment
Diethylcarbanozine (DEC) is effective.
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