Introduction
This is a parasitic and debilitating disease caused by the
filarial worm. It is caused by 3 distinct species of filarial worms namely Wuchereria bancrofti, Brugiamalayi and Brugiatimori.
It affects the legs, scrotum and the breasts. Transmission
occurs through the bite of mosquitoes (vetor) species, aedes, culex, anopheles
& mansonia.
The W.Buncrofti is strictly a human pathogen and it is
distributed in tropical areas worldwide whereas B.malayi & B.timori infects
a number of wild and domestic animals.
Life Cycle
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Filariform larvae enters the human body during a mosquito
bite and migrate to the nearest lymph gland where they mature into the thread
like adult worms about 3 months to 1 year later. The adult produces sheathed
microfilariae that migrate into lymph and blood channels. Mosquitoes pick up
the microfilaria when they bite or feed on man. In the lymphatic channels, the
worm dies and produces fibro-proliferative granuloma which obstruct the lymph
channels causing lymphoedoma & elephantiasis. Once the microfilariae enters
the mosquito through blood meal, they penetrate the insect’s midgut and move to
the thoracic muscle where they mature into infective Iarvae.
Signs and Symptoms
- Acute
lymphangitis with fever & chills.
- Arthritis;
knee and ankle joints warm, tender and painful.
- Chyluria: leaks
of lymphatic fluid into the kidneys and turns the urine milky white.
- Lymphadenitis;
swollen lymph nodes.
- Lymphoedena
Treatment
- Ivermectin
(this drug should not be given to pregnant woman and children less than 4years),
Albendazole, DEC (diethylcarbamazine) are good micro filaricides.
- Surgery to
open up the lymph flow.
- Antibiotics
for bacterial infections.
- Elevation of
the limb and the use of elastic pressure bandages.
Diagnosis
- Blood sample
collected at night and examined under microscope.
- Clinical
features.
Prevention of Filariasis
- Avoid
mosquito bite by;
- Using
mosquito net at night.
- Wearing
protective clothing like long sleeve shirts and long trousers at night.
- Using
mosquito repellent at night.
- Prevent the
breading of mosquito larvae by;
- Always
keeping the environment clean.
- Draining all
standing waters or pouring oil over stagnant waters.
- Spraying the
breeding sites with chemicals.
- Providing
proper refuse disposal methods.
- People in
endemic area like Africa should take chemoprophylaxis e.g. S.P.
- Prompt
treatment of all infected persons.
- Annual mass treatment with ivermectin.
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