Wuchereria bancrofti Life Cycle

1. When feeding from a human host, an infected mosquito transmits third-stage (L3) filarial larvae onto the skin of the host. The larvae then penetrate via the bite wound.

2. Infective larvae migrate to the lymphatics, where they develop into threadlike adult worms.

3. Gravid adult females produce sheathed microfilariae that circulate in lymph and blood.

4. A mosquito ingests the microfilariae when feeding from the infected host.

5. After ingestion, the microfilariae lose their sheaths. Some of them work their way through portions of the mosquito’s midgut and migrate to its thoracic muscles.

6 and 7. In the thoracic muscles, the microfilariae develop into first-stage (L1) larvae and subsequently into third-stage (L3) infective larvae.

8. Third-stage infective larvae migrate to the mosquito’s proboscis. The life cycle is complete when the mosquito feeds on a host.