Mansonella perstans lifecycle

During a blood meal, an infected midge (genus Culicoides) introduces third-stage filarial larvae onto the skin of the human host, where they penetrate into the bite wound (1). They develop into adults that reside in body cavities, most commonly the peritoneal cavity or pleural cavity, but less frequently in the pericardium (2). The size range for female worms is 70 to 80 mm in length and 120 mcm in diameter, and the males measure approximately 45 mm by 60 mcm. Adults produce unsheathed and subperiodic microfilariae, measuring 200 by 4.5 mcm, which reach the blood stream (3). A midge ingests microfilariae during a blood meal (4). After ingestion, the microfilariae migrate from the midge's midgut through the hemocoel to the thoracic muscles of the arthropod (5). There the microfilariae develop into first-stage larvae (6) and subsequently into third-stage infective larvae (7). The third-stage infective larvae migrate to the midge's proboscis (8) and can infect another human when the midge takes a blood meal (1).