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Brugia malayi is one of the eight parasitic nematode (roundworm) species that account for most cases of filariasis in humans. This form of filariasis is known as lymphatic filariasis. Brugia malayi is one of the three of these eight species responsible for most of the morbidity attributable to filariasis (the other two being Wuchereria bancrofti, which also causes lymphatic filariasis, and Onchocerca volvulus, which causes onchocerciasis (river blindness)). Brugia malayi is limited to Asia. (Centers for Disease Control Parasites and Health website)
The typical vectors for Brugia malayi filariasis are Mansonia and Aedes mosquitoes. During a blood meal, an infected mosquito introduces third-stage filarial larvae onto the skin of a human host, where they penetrate into the bite wound. They larvae develop into adults that commonly reside in the lymphatics. The adult worms resemble those of Wuchereria bancrofti but are smaller. Female worms measure 43 to 55 mm in length by 130 to 170 μm in width and males measure 13 to 23 mm in length by 70 to 80 μm in width. Adults produce microfilariae, measuring 177 to 230 μm in length and 5 to 7 μm in width, which are sheathed and have nocturnal periodicity. The microfilariae migrate into lymph and enter the blood stream, reaching the peripheral blood. A mosquito ingests the microfilariae during a blood meal. After ingestion, the microfilariae lose their sheaths and work their way through the wall of the proventriculus and cardiac portion of the midgut to reach the thoracic muscles. There the microfilariae develop into first-stage larvae and subsequently into third-stage larvae. The third-stage larvae migrate through the hemocoel to the mosquito's prosbocis and can infect another human when the mosquito takes a blood meal. (Centers for Disease Control Parasites and Health website)
Svott and Ghedin (2008) presented an analysis of the genome of B. malayi.