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[Brugia malayi] [Brugia timori] [Dirofilaria spp.] [Loa loa] [Mansonella ozzardi] [Mansonella perstans] [Mansonella streptocerca] [Onchocerca volvulus] [Wuchereria bancrofti]

During a blood meal, an infected mosquito (Aedes, Anopheles, and possibly others) introduces third-stage filarial larvae of Dirofilaria tenuis onto the skin of the raccoon definitive host (but also occasionally humans), where they penetrate into the bite wound .  In the definitive host, the L3 larvae undergo two more molts into L4 and adults, the latter of which resides in subcutaneous tissues .  Adult females are usually 80-130 mm long by 260-360 µm wide; males are usually 40-50 mm long by 190-260 µm wide.  Adults can live for 5 - 10 years.  In subcutaneous tissue, the female worms are capable of producing microfilariae over their lifespan.  The microfilariae are found in peripheral blood .  A mosquito ingests the microfilariae during a blood meal .  After ingestion, the microfilariae migrate from the mosquito’s midgut through the hemocoel to the Malpighian tubules in the abdomen .  There the microfilariae develop into first-stage larvae and subsequently into third-stage infective larvae .  The third-stage infective larvae migrate to the mosquito's proboscis and can infect another definitive host when it takes a blood meal .  In humans , D. tenuis may wander in the subcutaneous tissues for months, but finally is encapsulated in a granulomatous nodule, but may also be found around the eye or on the conjunctiva.  Because of this, the infection in humans was first known as Dirofilaria conjunctivae.