microfilaria

nematode larva

Also known as: microfilariae

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Last updated

June 30, 2026

Quick Summary

Microfilariae are the larval stage of filarial worms, which are parasitic nematodes. These worms require two hosts to complete their life cycle: an arthropod, like a mosquito, and a vertebrate, such as a human. The female worm releases microscopic microfilariae into the bloodstream of the vertebrate host. When an infected arthropod bites the vertebrate, it ingests the microfilariae. Inside the arthropod, the microfilariae develop into infective larvae, which are then transmitted to another vertebrate host during a subsequent bite. In mammals, these worms cause diseases collectively known as filariasis, including conditions like elephantiasis and river blindness.12

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eye worm
…of microscopic, active embryos called microfilariae, which enter the host’s blood or lymph vessels. Some of these are ingested by a deerfly as it sucks blood and, after about two weeks, complete a series of growth stages. As infective larvae, they move to the insect’s proboscis to await an opportunity…
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…of microscopic, active embryos called microfilariae, which enter the host’s blood or lymph vessels. Some of these are ingested by a deerfly as it sucks blood and, after about two weeks, complete a series of growth stages. As infective larvae, they move to the insect’s proboscis to await an opportunity…
Read More

filariasis
Cycle of infection and symptoms
…birth to elongated embryos, the microfilariae, which are taken up by an intermediate host. Microfilariae migrate through the peripheral blood and skin, from which they are taken by bloodsucking insects. Within the insect carrier, the microfilariae grow into motile infective larvae that, at the insect’s next blood meal, are introduced…
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…birth to elongated embryos, the microfilariae, which are taken up by an intermediate host. Microfilariae migrate through the peripheral blood and skin, from which they are taken by bloodsucking insects. Within the insect carrier, the microfilariae grow into motile infective larvae that, at the insect’s next blood meal, are introduced…
Read More