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Study Notes

W. bancrofti, B. malayi, and B. timori are parasites that have five distinct life cycle stages.
Adult female worms release up to 10,000 first-stage larvae or microfilariae per day, which circulate in blood.
Microfilariae are most abundant in the circulation at night (nocturnal periodicity) and sequester in the deep vascular beds during the day.
Microfilariae are ingested by mosquitoes and exsheath after the blood meal, penetrate the mosquito gut wall, and migrate to the mosquito's thoracic muscle where they grow and undergo two molts to infective third-stage larvae (L3) in 10 to 14 days.
The L3 actively enter the feeding site, migrate to the local lymphatics where they quickly molt to L4-stage larvae, and then migrate centrally in the lymphatic systems to develop into sexually mature, adult worms at 6 to 9 months.
Adult worms are long, threadlike organisms and have the ability to cause massive dilation of the surrounding and proximal lymphatics.
The type and extent of overt clinical disease are related to where adult worms accumulate.
Infected persons can exhibit acute manifestations, particularly acute filarial lymphangitis (AFL) and acute dermatolymphangioadenitis (ADLA).
The adenolymphangitis of brugian filariasis is distinct, dramatic, and destructive.
Brugian filariasis does not cause urogenital disease and chyluria.